1 OFFICE PROPERTIES INCOME TRUST INVESTOR PRESENTATION Q4 2022 Washington, DC

2 OFFICE PROPERTIES INCOME TRUST This presentation contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 and other securities laws. Also, whenever we use words such as “believe”, “expect”, “anticipate”, “intend”, “plan”, “estimate”, “will”, “may” and negatives or derivatives of these or similar expressions, we are making forward-looking statements. These forward-looking statements are based upon our present intent, beliefs or expectations, but forward-looking statements are not guaranteed to occur and may not occur. Forward-looking statements in this presentation relate to various aspects of our business, including: the extent to which changes in office space utilization, including remote work arrangements, will continue and the impact that may have on demand for office space at our properties; our ability and the ability of the office real estate sector and our tenants to operate under unfavorable market and economic conditions, such as rising or sustained high interest rates and high inflation, labor market challenges, volatility in the public equity and debt markets, geopolitical instability and economic downturns or recessions; our expectations about the financial strength of our tenants; our expectations regarding the costs and timing of development, redevelopment and repositioning activities; the likelihood that our tenants will renew or extend their leases and not exercise early termination options or that we will obtain replacement tenants on terms as favorable to us as our prior leases; our belief that we are in a position to opportunistically recycle and deploy capital; the likelihood that our tenants will pay rent or be negatively affected by cyclical economic conditions or government budget constraints; our ability to pay distributions to our shareholders and to maintain or increase the amount of such distributions; our expectations regarding occupancy at our properties; our expectations regarding our cash available for distribution payout ratio; our expectations regarding our future financial performance including funds from operations, or FFO, normalized funds from operations, or Normalized FFO, net operating income, or NOI, and cash basis NOI; our expectations regarding demand for leased space; our expectations regarding capital expenditures, including as a result of inflation or supply chain challenges; our expectations regarding possible acquisitions and sales of properties, including the targeted proceeds of the properties we are currently marketing for sale; our policies and plans regarding investments, financings and dispositions; our ability to raise and balance our use of debt and equity capital; our ability to make required payments on our debt; our ability to maintain sufficient liquidity, including the availability of borrowings under our revolving credit facility, and otherwise manage leverage; our credit ratings; our expectation that we benefit from our relationships with The RMR Group LLC, or RMR; our qualification for taxation as a real estate investment trust, or REIT; changes in federal or state tax laws; and other matters. Our actual results may differ materially from those contained in or implied by our forward-looking statements as a result of various factors, such as: the impact of increasing or sustained high interest rates, inflation, labor market challenges, volatility in the public equity and debt markets, the commercial real estate industry in general, geopolitical instability and economic downturns or recessions, the commercial real estate industry on us and our tenants; competition within the commercial real estate industry, particularly in those markets in which our properties are located; the impact of changes in the real estate needs and financial conditions of our tenants; compliance with, and changes to, federal, state and local laws and regulations, accounting rules, tax laws and similar matters; the impact of any U.S. government shutdown or failure to increase the government debt ceiling on our ability to collect rents and pay our operating expenses, debt obligations and distributions to shareholders on a timely basis; actual and potential conflicts of interest with our related parties, including our Managing Trustees, RMR, Sonesta International Hotels Corporation, or Sonesta, and others affiliated with them; limitations imposed by and our ability to satisfy complex rules to maintain our qualification for taxation as a REIT for U.S. federal income tax purposes; and acts of terrorism, outbreaks or continuation of pandemics or other public health safety events or conditions, war or other hostilities, further material or prolonged disruption to supply chains, or other manmade or natural disasters beyond our control. Our Annual Report on Form 10-K for the year ended December 31, 2022 and our other filings with the Securities and Exchange Commission, or SEC, including under the caption “Risk Factors”, identify other important factors that could cause differences from our forward-looking statements. Our filings with the SEC are available on the SEC’s website at www.sec.gov. You should not place undue reliance upon our forward-looking statements. Except as required by law, we do not intend to update or change any forward-looking statements as a result of new information, future events or otherwise. Notes Regarding Certain Information in this Presentation This presentation contains industry and statistical data that we obtained from various third party sources. Nothing in the data used or derived from third party sources should be construed as investment advice. Some data and other information presented are also based on our good faith estimates and beliefs, derived from our review of internal surveys and independent sources and our experience. We believe that these external sources, estimates and beliefs are reliable and reasonable, but we have not independently verified them. Although we are not aware of any misstatements regarding the data presented herein, these estimates and beliefs involve inherent risks and uncertainties and are based on assumptions that are subject to change. Unless otherwise expressly noted, (1) all data presented are as of or for the three months ended December 31, 2022, (2) references to “weighted average” mean a weighted average by annualized rental income, (3) references to “annualized rental income” mean the annualized contractual rents, as of December 31, 2022, including straight line rent adjustments and excluding lease value amortization, adjusted for tenant concessions, including free rent and amounts reimbursed to tenants, plus estimated recurring expense reimbursements from tenants (annualized rental income may differ from actual historical rental revenues calculated pursuant to U.S. Generally Accepted Accounting Principles, or GAAP), and (4) all data presented excludes three properties, which are encumbered by $82.0 million of mortgage notes, owned by two unconsolidated joint ventures in which we own 51% and 50% interests. Non-GAAP Financial Measures This presentation contains non-GAAP financial measures including FFO, Normalized FFO, Cash Available for Distribution, EBITDA, EBITDAre, Adjusted EBITDAre, NOI and Cash Basis NOI. Calculations of, and reconciliations for these metrics to the closest GAAP metrics, are included in an Appendix hereto. Please refer to Non-GAAP Financial Measures and Certain Definitions in the Appendix for terms used throughout this presentation. WARNING REGARDING FORWARD LOOKING STATEMENTS, DISCLAIMERS AND NON-GAAP FINANCIAL MEASURES

3 OFFICE PROPERTIES INCOME TRUST a. Total gross assets. b. Based on annualized rental income. See Appendix herein for our definition of investment grade tenants. OPI AT A GLANCE 21.0 MILLION SQUARE FEET $567 Million TOTAL LIQUIDITY $4.5 Billion INVESTMENT PORTFOLIO(1) 90.6% OCCUPANCY 160 PROPERTIES IN PORTFOLIO 63% REVENUE FROM INVESTMENT GRADE TENANTS(2) Office Properties Income Trust (Nasdaq: OPI) is an investment grade rated real estate investment trust (REIT) focused on a diverse portfolio of high-quality office and mixed-use properties in select growth-oriented U.S. markets. OPI was named as an Energy Star® Partner of the Year for the fifth consecutive year and a Green Lease Leader. (1) Total gross assets. (2) Based on annualized rental income. See Appendix herein for our definition of investment grade tenants. 3

4 OFFICE PROPERTIES INCOME TRUST RECENT COMPANY HIGHLIGHTS Fourth Quarter 2022 Full Year 2022 • Reported strong leasing momentum, solid financial results and further execution of capital recycling plans. • Completed 705,000 square feet of leasing, representing the highest quarterly retention in three years. • Maintained portfolio occupancy above 90%. • Net Income and Normalized FFO of $0.13 per share and $1.13 per share, respectively. • Executed 2.6 million square feet of leasing at a 5.6% roll-up in rent and 9 year WALT. • Sold 21 non-core properties consisting of 2.4 million square feet for more than $216 million.(1) • Increased portfolio occupancy 110 basis points to 90.6%. • Invested in the redevelopment of two properties in Washington, D.C. and Seattle, WA. • Named as a Green Lease Leader and Energy Star® Partner of the Year for the fifth consecutive year. • Continued to pay dividends of $0.55 per share per quarter, or $2.20 annually. (1) Reflects activity through January 2023. Fort Mill, SC

5 OFFICE PROPERTIES INCOME TRUST (1) Based on annualized rental income. See Appendix herein for our definition of investment grade tenants. COMPELLING INVESTMENT OPPORTUNITY Diversified Portfolio Secure and Stable Income Investment Grade Balance Sheet Capital Recycling Strategy Dividend Coverage Commitment to ESG • By geography, use, tenant and industry. • A focus on strong, growing markets. • 63% of annualized rental income comes from investment grade rated tenants.(1) • Diversified portfolio of office and mixed-use assets. • More than $550 million of liquidity. • Well-laddered debt maturities. • Enhance portfolio quality. • Generate CAD accretion. • Manage leverage levels. • Normalized FFO payout ratio of 49%. • Rolling four quarter CAD payout ratio of 84%. • 2022 ENERGY STAR® Partner of the Year. • Named a Gold Level 2022 Green Lease Leader. • Designated a 2020 Women on Boards “Winning” company.

6 OFFICE PROPERTIES INCOME TRUST Phoenix DIVERSIFIED ACROSS STRATEGIC U.S. MARKETS Chicago 11% D.C. Metro(1)(2) 23% Atlanta 9% Silicon Valley/ Sacramento 10% Dallas 5% OPI Strategic Markets % Annualized Rental Income Focused on markets with strong economics and favorable long-term demand outlook. Boston 4% 6 Seattle(1) 1% Denver 2% Kansas City 4% Top Markets Based on Annualized Rental Income % Total Annualized Rental Income No. of Properties Property SF (‘000) Weighted Average Remaining Lease Term Chicago, IL 10.8% 5 1,674 5.9 DC 10.5% 7 1,317 9.8 Atlanta, GA 9.0% 11 2,024 8.1 Northern Virginia 8.4% 13 1,741 7.7 Silicon Valley, CA 5.7% 11 827 4.4 Dallas, TX 4.6% 8 1,491 3.0 Kansas City, MO 4.4% 3 770 9.8 Sacramento, CA 4.1% 7 882 3.4 Boston, MA 3.8% 8 805 2.6 Maryland 3.7% 5 753 6.2 Provo, UT 2.9% 3 537 8.7 Indianapolis, IN 2.4% 5 709 3.0 Total 70.3% 86 13,530 6.1 LEED, BOMA, and/or ENERGY STAR Certified Building Seattle, WA Sacramento, CA Tampa, FL Chicago, IL L Malden, MA Lakewood, CO (1) Redevelopment project in process. (2) Includes the District of Columbia, Northern Virginia and Maryland.

7 OFFICE PROPERTIES INCOME TRUST SECURE AND STABLE INCOME U.S. Government 19.7% Other Government 8.8% Government Contractors 6.4% Real Estate & Financial 16.7% Technology & Communications 15.5% Legal & Other Professional Services 11.5% Manufacturing & Transportation 10.6% Life Science and Medical 3.2% Other 7.6% Tenant Credit Profile % Total Annualized Rental Income Top 20 Tenants % Total Annualized Rental Income 1 U.S. Government 19.7% 2 Alphabet Inc. (Google) 3.9% 3 Shook, Hardy & Bacon L.L.P. 3.6% 4 IG Investments Holdings LLC 3.1% 5 State of California 2.9% 6 Bank of America Corporation 2.9% 7 Commonwealth of Massachusetts 2.3% 8 CareFirst Inc. 2.1% 9 Tyson Foods, Inc. 2.0% 10 Sonesta International Hotels Corporation (1) 2.0% 11 Northrop Grumman Corporation 2.0% 12 CommScope Holding Company Inc. 1.7% 13 Sonoma Biotherapeutics, Inc. (2) 1.4% 14 State of Georgia 1.4% 15 PNC Bank 1.3% 16 Micro Focus International plc 1.3% 17 Compass Group plc 1.2% 18 ServiceNow, Inc. 1.2% 19 Allstate Insurance Co. 1.2% 20 Leidos Holdings Inc. 1.1% Total 58.3% Tenant Industry % Total Annualized Rental Income (1) In June 2021, we entered into a 30-year lease with Sonesta. The lease relates to the redevelopment of a property we own in Washington, D.C to a mixed use and Sonesta's lease relates to the planned hotel component of the property. The term of the lease commences upon our delivery of the completed hotel, which is estimated to occur in the second quarter of 2023. (2) In August 2022, we entered into an approximately 10-year lease with Sonoma Biotherapeutics, Inc. The lease is at a property we own in Seattle, WA that is currently undergoing redevelopment. The term of the lease is estimated to commence in the fourth quarter of 2023. Non-Investment Grade 7.6% Not Rated 29.7% Investment Grade 62.7% nt t Total Government 34.9%

8 OFFICE PROPERTIES INCOME TRUST GROWTH STRATEGY Positioned to advance core business strategies focused on enhancing the overall quality and geographic footprint of the portfolio. Organic Growth • Maintain high occupancy through best-in-class operations and service centered tenant relationships. • Drive portfolio absorption through proactive asset management and leasing. • Focus on retention and opportunities to grow rents. Capital Recycling • Sell properties older in age, capital intensive, or that have maximized value. • Exit markets with limited future rent growth. • Reinvest proceeds into higher quality properties with strong cash flows. • Target modern and highly functional properties in growing markets. • Manage leverage levels. Development • Create user-centered experiences through select development opportunities. • Focus on markets with strong economic growth providing for enhanced risk-adjusted returns. • Deliver sustainable buildings with an emphasis on LEED, wellness, and reduction of the portfolio carbon footprint. • Enhance buildings and local communities through a people centric “place-making” approach.

9 OFFICE PROPERTIES INCOME TRUST 4.2% 6.9% 6.3% 5.6% -1% 1% 3% 5% 7% 9% 11% 13% 15% 0 500 1000 1500 2000 2500 3000 3500 2019 2020 2021 2022 Renewals New Leasing Leasing Roll-up/down 2.6M SF New and renewal leasing Leasing Activity (SF in 000s) PROACTIVE ASSET MANAGEMENT AND LEASING Staggered Lease Expirations % Total Annualized Rental Income Expiring 5.6% Roll up in rent 9.3 years WALT Trailing Twelve Months Completed Activity 2.7M SF including 1.1M SF of new leasing 541K SF Potential to absorb vacant space Leasing Pipeline 4-6% Mark to market potential Completed 588 thousand SF of new leasing activity during 2022 Actively managing lease expirations amid challenging office sector fundamentals 2,934 1,965 2,484 2,562 11.2% 14.7% 7.6% 7.3% 9.6% 49.6% 2023 2024 2025 2026 2027 2028+

10 OFFICE PROPERTIES INCOME TRUST • Completed $216 million of property sales.(1) • Two properties under agreement for $7.6 million. STRATEGIC CAPITAL RECYCLING Since 2019, OPI has sold approximately $1.5 billion of assets and redeployed proceeds into more attractive markets. Property Acquisitions & Dispositions ($ millions) Potential Benefits Reduce the average age of our portfolio. Reshape geographic and tenant diversification. Lengthen the weighted average term of our leases. Enhance leasing prospects and tenant retention. Manage ongoing capital requirements. 2019 2020 2021 2022 • Completed $849 million of property sales. • Sold all common shares of The RMR Group for $105 million. • Completed $110 million of property sales. • Acquired RoundPoint Mortgage HQ in the Charlotte MSA for $35 million and an acquisition in the Boston CBD. • Completed $227 million of property sales. • Redeployed proceeds into three acquisitions of office properties in Chicago, Atlanta and Boston for $577 million. (1) Reflects activity through January 31, 2023. $3 $47 $577 $849 $110 $227 $216 2019 2020 2021 2022 Acquisitions Dispositions - (1)

11 OFFICE PROPERTIES INCOME TRUST Phoenix RECENT PORTFOLIO RESHAPING Investing in newer, less capital-intensive properties that improve geographic diversification, rent growth, portfolio metrics and the long-term stability of cash flows. Reducing Exposure Increasing Exposure • Huntsville, AL • Birmingham, AL • Fresno, CA • Richmond, VA • Chesapeake, VA • Chicago, IL • Atlanta, GA • Boston, MA 2.8 WALT (Years) 2022 Disposition Highlights(1) 2.4M SF 21 Properties 532K SF 1,819K SF 786K 531K SF SF 49K SF 346K SF 96% Occupancy 2021 Disposition Highlights 6 Properties 1.2 WALT (Years) 2.6M SF Key Activity 22 Average Age (Years) (1) Reflects activity through January 31, 2023. 140K SF

12 OFFICE PROPERTIES INCOME TRUST ACQUISITION FOCUS Focused on acquiring office properties in markets that have strong economic fundamentals to support rent growth. Properties in strong and growing markets with characteristics to attract and retain tenants. • Strategic to tenants. • Minimum remaining lease term of seven years. • Effective age of 10 years or less. • Specialty uses where remote work is less likely. • Characteristics supporting ESG initiatives. Primarily first-generation properties. • High probability of renewing the tenants in place. • Modest ongoing capital needs. • Mixed-use, single and multi-tenant opportunities. Atlanta, GA

13 OFFICE PROPERTIES INCOME TRUST RECENT ACQUISITIONS 1000 W. Fulton Street, Chicago, IL – “1K Fulton” $355.0 Million Purchase Price 4.7% GAAP Cap Rate 531,190 Square Feet 99.2% Percent Leased 6.6 Years WALT Google (73%) Primary Tenant 1224 Hammond Dr., Atlanta, GA - “Twelve24” $195.0 Million Purchase Price 6.3% GAAP Cap Rate 345,917 Square Feet 98.4% Percent Leased 14.2 Years WALT Insight Global (96%) Primary Tenant 446 Wrenplace Road Fort Mill, SC $35.1 Million Purchase Price 8.1% GAAP Cap Rate 150,000 Square Feet 100% Percent Leased 10.8 Years WALT RoundPoint Mortgage Primary Tenant LEED, BOMA, and/or ENERGY STAR Certified Building Note: Data as of the acquisition date of each property.

14 OFFICE PROPERTIES INCOME TRUST VALUE CREATION THROUGH SELECT REDEVELOPMENT “20 Mass” 20 Massachusetts Avenue, Washington, D.C. “Unison” 351, 401, 501 Elliott Ave, Seattle, WA ~$215 Million Total Project Cost 8% - 10% Stabilized Returns 54% Pre-Leased 427,000 Square Feet Mixed Use Use Q2 2023 Estimated Delivery ~$162 Million Total Project Cost 10% - 12% Stabilized Returns 300,000 Square Feet Life Science Use Q4 2023 Estimated Delivery 28% Pre-Leased

15 OFFICE PROPERTIES INCOME TRUST Atlanta, GA STRONG AND FLEXIBLE FINANCIAL HEALTH Debt Profile Liquidity Position $555M Available Revolving Credit Facility $12M Cash on Hand 4.0% Weighted Average Interest Rate on Debt Debt Metrics 48.0% Net Debt to Gross Book Value of Real Estate Assets Ba1 Moody’s (2) BBB-S&P Global (2) Maturity Schedule 7.3x Net Debt to Rolling Four Quarter Adjusted EBITDAre 5.1 Years Weighted Average Debt Maturity Term (1) In November 2022, we exercised our option to extend the maturity date of our revolving credit facility by six months to July 31, 2023. Subject to the payment of an extension fee and meeting certain other conditions, we may further extend the maturity date by one additional six month period. (2) A securities rating is not a recommendation to buy, sell or hold securities and may be subject to revision or withdrawal at any time. $245 $350 $650 $300 $350 $562 $- $100 $200 $300 $400 $500 $600 $700 2023 2024 2025 2026 2027 2028+ ($M) (1) Variable Rate 7.9% 92.1% Fixed Rate Secured 2.0% Unsecured 98.0%

16 OFFICE PROPERTIES INCOME TRUST For more information, please read The RMR Group’s 2021 Sustainability Report here. COMMITMENT TO SUSTAINABILITY • 2022 ENERGY STAR® Partner of the Year Award (fifth consecutive year). • 2022 Gold Level Green Lease Leader. • 2021 Green Lease Leader, Silver (earned in 2015, 2016, 2017, 2019 and 2020). • OPI’s Board comprised of 44% women and 11% members of underrepresented communities. • Designated a 2020 Women on Boards “Winning” company. ESG HIGHLIGHTS ACHIEVEMENTS CONTINUED ADVANCEMENT OF INITIATIVES • Encouraging consideration of ESG criteria in the broader context of investment and property management through Internal Sustainability Reporting Committee. • Leveraging diversity professional associations, such as Commercial Real Estate Women (CREW) and The Partnership, Inc., to attract a more diverse pool of candidates. • Supporting employee health and wellness with activities such as LiveWell Week, Work Out at Home, Good Eats and Pay it Forward competitions. • Anticipating new LEED Certification of 580 thousand SF in 2023. • Planning to integrate wellness initiatives across the portfolio. Plantation, FL Atlanta, GA Ewing, NJ LEED Certified Properties 6.1 million square feet BOMA 360 Certified Properties 5.1 million square feet ENERGY STAR Certified Properties 6.6 million square feet 37 36 43

17 OFFICE PROPERTIES INCOME TRUST Appendix Colorado Springs, CO

18 OFFICE PROPERTIES INCOME TRUST RMR’s Operations Include: National Multi-Sector Investment Platform OFFICE INDUSTRIAL GOVERNMENT MEDICAL OFFICE LIFE SCIENCE SENIOR LIVING HOTELS RETAIL RMR Managed Companies Nearly 2,100 Properties More than $16 Billion in Annual Revenues Over $37 Billion in AUM Over600 CRE Professionals More than 30 Offices Throughout the U.S. Financial Services: Real Estate Services: Business Services: Accounting Acquisitions/ Dispositions Administration Capital Markets Asset Management Human Resources Compliance/ Audit Construction/ Development Information Technology (IT) Finance/ Planning Engineering Investor Relations Treasury Leasing Marketing Tax Property Management Legal/ Risk Management OPI IS MANAGED BY THE RMR GROUP, AN ALTERNATIVE ASSET MANAGER The RMR Group, LLC Over 38,000 Employees

19 OFFICE PROPERTIES INCOME TRUST A WINNING TRADITION EPA’S ENERGY STAR Partner of the Year 2019 - 2022. 70 properties with EPA ENERGY STAR certifications 60 properties with BOMA designations. Ranked #2 for portfolio with most designations 56 properties with LEED designations SUSTAINABILITY Ranked Boston Globe’s Top Places to Work 2020, 2021, 2022 Women on Boards; Winning Organization 2020 Fortune Magazine’s Fastest Growing Companies ranked 75th 2019 RMR RECOGNITION in Retail Real Estate Ownership in Hotel Real Estate Ownership in Senior Living Real Estate Ownership in Office Real Estate Ownership in Industrial Real Estate Ownership Senior Living Operator Hotel Operator fice Real #7 #6 #3 #6 #4 #8 #13 #3 Truck Stop Operator

20 OFFICE PROPERTIES INCOME TRUST (1) Source: S&P Global Market Intelligence. Data is for the most recently reported twelve months as of February 22, 2023. RELATIONSHIP WITH RMR PROVIDES SCALE AND EFFICIENCY Key Benefits • RMR provides all the employees; OPI has no employees. • RMR’s acquisitions team has visibility to properties marketed for sale across the United States. • The depth and breadth of the RMR platform attracts strong real estate professionals. • Career advancement opportunities at RMR drives employee engagement and retention. • RMR property management employees focus only on assets managed by RMR. • RMR platform provides centralized support services, including procurement, banking and capital markets. G&A % of Total Revenue(1) 3.7% 4.5% 4.8% 5.0% 5.1% 5.2% 8.1% 8.4% OFC OPI BXP CIO HIW PDM DEA FSP

21 OFFICE PROPERTIES INCOME TRUST RMR base management fee tied to OPI share price performance. • Consists of an annual fee equal to generally 50 bps multiplied by the lower of: (1) OPI’s historical cost of real estate, or (2) OPI’s total market capitalization. • There is no incentive for RMR to complete any transaction that could reduce share price. RMR incentive fees contingent on total shareholder return outperformance. • Incentive management fee: 12% of the outperformance of our total return per share compared to the MSCI U.S. Office REIT Index over a three year period multiplied by equity market capitalization. • Outperformance must be positive to be earned. • Shareholders keep 100% of benchmark returns and at least 88% of returns in excess of the benchmark. Other fees. • Property management fee: consists of an annual fee based on 3.0% of rents collected at OPI’s managed properties. • Construction management fee based on 5.0% of project costs. Alignment of Interests If OPI’s share price goes up and its total market cap exceeds its historical cost of real estate; RMR base management fee is capped at 50 bps of historical cost of real estate. If OPI’s stock price goes down and its historical cost of real estate exceeds its total market cap; RMR gets less base management fees (50 bps on equity market cap plus debt). Incentive fee structure keeps RMR focused on increasing total shareholder return. Members of RMR senior management are holders of OPI common shares, some subject to long term lock up agreements. OPI shareholders have visibility into RMR, a publicly traded company. OPI benefits from RMR’s national footprint and economies of scale of $37 billion platform. FEES THAT OPI PAYS TO RMR ARE PRIMARILY PERFORMANCE BASED WHICH ALIGNS INTERESTS WITH SHAREHOLDERS

22 OFFICE PROPERTIES INCOME TRUST San Jose, CA Financials

23 OFFICE PROPERTIES INCOME TRUST KEY FINANCIAL DATA (dollars in thousands, except per share data) As of and for the Three Months Ended 12/31/2022 9/30/2022 6/30/2022 3/31/2022 12/31/2021 Selected Balance Sheet Data: Total gross assets $ 4,541,435 $ 4,507,422 $ 4,578,277 $ 4,703,791 $ 4,737,595 Total assets $ 3,979,977 $ 3,968,986 $ 4,062,658 $ 4,197,693 $ 4,241,683 Total liabilities $ 2,593,642 $ 2,562,821 $ 2,647,208 $ 2,740,611 $ 2,744,974 Total shareholders' equity $ 1,386,335 $ 1,406,165 $ 1,415,450 $ 1,457,082 $ 1,496,709 Selected Income Statement Data: Rental income $ 127,922 $ 137,683 $ 141,316 $ 147,354 $ 147,287 Net income (loss) $ 6,390 $ 16,964 $ (16,056) $ (13,407) $ 16,945 NOI $ 84,617 $ 85,546 $ 92,416 $ 96,481 $ 92,379 Adjusted EBITDAre $ 79,479 $ 79,957 $ 86,422 $ 91,241 $ 86,304 FFO $ 55,186 $ 53,802 $ 58,622 $ 62,722 $ 62,567 Normalized FFO $ 54,495 $ 53,802 $ 58,923 $ 62,722 $ 58,083 Rolling four quarter CAD $ 126,701 $ 159,550 $ 162,355 $ 158,363 $ 155,009 Per Common Share Data (basic and diluted): Net income (loss) $ 0.13 $ 0.35 $ (0.33) $ (0.28) $ 0.35 FFO $ 1.14 $ 1.11 $ 1.21 $ 1.30 $ 1.30 Normalized FFO $ 1.13 $ 1.11 $ 1.22 $ 1.30 $ 1.20 Rolling four quarter CAD $ 2.62 $ 3.30 $ 3.36 $ 3.28 $ 3.21 Dividends: Annualized dividends paid per share during the period $ 2.20 $ 2.20 $ 2.20 $ 2.20 $ 2.20 Annualized dividend yield (at end of period) 16.5% 15.7% 11.0% 8.6% 8.9% Normalized FFO payout ratio 48.7% 49.5% 45.1% 42.3% 45.8% Rolling four quarter CAD payout ratio 84.0% 66.7% 65.5% 67.1% 68.5%

24 OFFICE PROPERTIES INCOME TRUST DEBT SUMMARY 1. Reflects the interest rate stated in, or determined pursuant to, the contract terms. 2. Includes the effect of mark to market accounting for certain mortgages and discounts on senior unsecured notes. Excludes the effect of debt issuance costs amortization. 3. We are required to pay interest on borrowings under our revolving credit facility at a rate of LIBOR plus a premium of 110 basis points per annum. We also pay a facility fee of 25 basis points per annum on the total amount of lending commitments under our revolving credit facility. Both the interest rate premium and facility fee are subject to adjustment based upon changes to our credit ratings. The interest rate listed is as of December 31, 2022 and excludes the 25 basis point facility fee. In November 2022, we exercised our option to extend the maturity date of our revolving credit facility by six months to July 31, 2023. Subject to the payment of an extension fee and meeting certain other conditions, we may further extend the maturity date by one additional six month period. 4. The maximum aggregate borrowing availability under the credit agreement governing our revolving credit facility may be increased to up to $1,950,000 in certain circumstances. As of December 31, 2022: (dollars in thousands) Coupon Rate (1) Interest Rate (2) Principal Balance Maturity Date Due at Maturity Years to Maturity Unsecured Floating Rate Debt: $750,000 unsecured revolving credit facility (3) (4) 5.444% 5.444% $ 195,000 7/31/2023 $ 195,000 0.6 Unsecured Fixed Rate Debt: Senior unsecured notes due 2024 4.250% 4.404% 350,000 5/15/2024 350,000 1.4 Senior unsecured notes due 2025 4.500% 4.521% 650,000 2/1/2025 650,000 2.1 Senior unsecured notes due 2026 2.650% 2.815% 300,000 6/15/2026 300,000 3.5 Senior unsecured notes due 2027 2.400% 2.541% 350,000 2/1/2027 350,000 4.1 Senior unsecured notes due 2031 3.450% 3.550% 400,000 10/15/2031 400,000 8.8 Senior unsecured notes due 2050 6.375% 6.375% 162,000 6/23/2050 162,000 27.5 Subtotal / weighted average 3.825% 3.918% 2,212,000 2,212,000 5.6 Secured Fixed Rate Debt: Mortgage debt - One property in Chicago, IL 3.700% 4.210% 50,000 6/1/2023 50,000 0.4 Total / weighted average 3.951% 4.045% $2,457,000 $ 2,457,000 5.1

25 OFFICE PROPERTIES INCOME TRUST CALCULATION OF NOI AND CASH BASIS NOI 1. We recorded a liability for the amount by which the estimated fair value for accounting purposes exceeded the price we paid for our former investment in The RMR Group Inc. common stock in June 2015. A portion of this liability is being amortized on a straight line basis through December 31, 2035 as a reduction to property management fees expense, which are included in property operating expenses. (dollars in thousands) For the Three Months Ended 12/31/2022 9/30/2022 6/30/2022 3/31/2022 12/31/2021 Calculation of NOI and Cash Basis NOI: Rental income $ 127,922 $ 137,683 $ 141,316 $ 147,354 $ 147,287 Property operating expenses (43,305) (52,137) (48,900) (50,873) (54,908) NOI 84,617 85,546 92,416 96,481 92,379 Non-cash straight line rent adjustments included in rental income (3,604) (1,765) (2,775) (2,686) (2,240) Lease value amortization included in rental income 195 204 233 343 452 Lease termination fees included in rental income (176) (83) (2,175) (4,942) (761) Non-cash amortization included in property operating expenses(1) (121) (121) (121) (121) (121) Cash Basis NOI $ 80,911 $ 83,781 $ 87,578 $ 89,075 $ 89,709 Reconciliation of Net Income (Loss) to NOI and Cash Basis NOI: Net income (loss) $ 6,390 $ 16,964 $ (16,056) $ (13,407) $ 16,945 Equity in net losses of investees 878 952 833 846 837 Income tax expense (benefit) (161) 90 (190) 531 (97) Income (loss) before income tax expense (benefit) and equity in net losses of investees 7,107 18,006 (15,413) (12,030) 17,685 (Gain) loss on early extinguishment of debt (759) — 77 — — Interest expense 24,557 24,969 26,515 27,439 27,657 Interest and other income (144) (56) (16) (1) — (Gain) loss on sale of real estate (3,564) (16,925) 11,637 (2,149) (24,200) General and administrative 5,781 6,564 7,083 5,706 2,168 Acquisition and transaction related costs 68 — 224 — — Loss on impairment of real estate — — 4,773 17,047 6,566 Depreciation and amortization 51,571 52,988 57,536 60,469 62,503 NOI 84,617 85,546 92,416 96,481 92,379 Non-cash amortization included in property operating expenses (1) (121) (121) (121) (121) (121) Lease termination fees included in rental income (176) (83) (2,175) (4,942) (761) Lease value amortization included in rental income 195 204 233 343 452 Non-cash straight line rent adjustments included in rental income (3,604) (1,765) (2,775) (2,686) (2,240) Cash Basis NOI $ 80,911 $ 83,781 $ 87,578 $ 89,075 $ 89,709

26 OFFICE PROPERTIES INCOME TRUST CALCULATION OF EBITDA, EBITDAre AND ADJUSTED EBITDAre 1. Amounts represent equity based compensation to our Trustees, our officers and certain other employees of RMR. 2. Incentive fees under our business management agreement with RMR are payable after the end of each calendar year, are calculated based on common share total return, as defined, and are included in general and administrative expense in our consolidated statements of income (loss). In calculating net income (loss) in accordance with GAAP, we recognize estimated business management incentive fee expense, if any, in the first, second and third quarters. Although we recognize this expense, if any, in the first, second and third quarters for purposes of calculating net income (loss), we do not include such expense in the calculation of Adjusted EBITDAre until the fourth quarter, when the amount of the business management incentive fee expense for the calendar year, if any, is determined. (dollars in thousands) For the Three Months Ended 12/31/2022 9/30/2022 6/30/2022 3/31/2022 12/31/2021 Net income (loss) $ 6,390 $ 16,964 $ (16,056) $ (13,407) $ 16,945 Add (less): Interest expense 24,557 24,969 26,515 27,439 27,657 Income tax expense (benefit) (161) 90 (190) 531 (97) Depreciation and amortization 51,571 52,988 57,536 60,469 62,503 EBITDA 82,357 95,011 67,805 75,032 107,008 Add (less): Loss on impairment of real estate — — 4,773 17,047 6,566 (Gain) loss on sale of real estate (3,564) (16,925) 11,637 (2,149) (24,200) Distributions received from unconsolidated joint ventures — — — 51 153 Equity in losses of unconsolidated joint ventures 878 952 833 846 837 EBITDAre 79,671 79,038 85,048 90,827 90,364 Add (less): Acquisition and transaction related costs 68 — 224 — — General and administrative expense paid in common shares (1) 499 919 1,073 414 424 Business management incentive fees (2) — — — — (4,484) (Gain) loss on early extinguishment of debt (759) — 77 — — Adjusted EBITDAre $ 79,479 $ 79,957 $ 86,422 $ 91,241 $ 86,304

27 OFFICE PROPERTIES INCOME TRUST CALCULATION OF FFO, NORMALIZED FFO AND CAD 1. Incentive fees under our business management agreement with RMR are payable after the end of each calendar year, are calculated based on common share total return, as defined, and are included in general and administrative expense in our consolidated statements of income (loss). In calculating net income (loss) in accordance with GAAP, we recognize estimated business management incentive fee expense, if any, in the first, second and third quarters. Although we recognize this expense, if any, in the first, second and third quarters for purposes of calculating net income (loss), we do not include such expense in the calculation of Normalized FFO until the fourth quarter, when the amount of the business management incentive fee expense for the calendar year, if any, is determined. 2. Non-cash expenses include equity based compensation, adjustments recorded to capitalize interest expense and amortization of the liability for the amount by which the estimated fair value for accounting purposes exceeded the price we paid for our former investment in RMR Inc.’s common stock in June 2015. This liability is being amortized on a straight line basis through December 31, 2035 as an allocated reduction to business management fee expense and property management fee expense, which are included in general and administrative and other operating expenses, respectively. (dollars in thousands, except per share data) For the Three Months Ended 12/31/2022 9/30/2022 6/30/2022 3/31/2022 12/31/2021 Net income (loss) $ 6,390 $ 16,964 $ (16,056) $ (13,407) $ 16,945 Add (less): Depreciation and amortization: Consolidated properties 51,571 52,988 57,536 60,469 62,503 Unconsolidated joint venture properties 789 775 732 762 753 Loss on impairment of real estate — — 4,773 17,047 6,566 (Gain) loss on sale of real estate (3,564) (16,925) 11,637 (2,149) (24,200) FFO 55,186 53,802 58,622 62,722 62,567 Add (less): Acquisition and transaction related costs 68 — 224 — — (Gain) loss on early extinguishment of debt (759) — 77 — — Business management incentive fees (1) — — — — (4,484) Normalized FFO 54,495 53,802 58,923 62,722 58,083 Add (less): Non-cash expenses (2) (1,464) (640) (192) (465) (251) Distributions from unconsolidated joint ventures — — — 51 153 Depreciation and amortization - unconsolidated joint ventures (789) (775) (732) (762) (753) Equity in net losses of investees 878 952 833 846 837 Non-cash straight line rent adjustments included in rental income (3,604) (1,765) (2,775) (2,686) (2,240) Lease value amortization included in rental income 195 204 233 343 452 Net amortization of debt premiums, discounts and issuance costs 2,188 2,176 2,366 2,404 2,405 Recurring capital expenditures (42,099) (25,882) (20,833) (11,447) (16,037) CAD $ 9,800 $ 28,072 $ 37,823 $ 51,006 $ 42,649 Weighted average common shares outstanding (basic) 48,334 48,286 48,249 48,243 48,243 Weighted average common shares outstanding (diluted) 48,334 48,286 48,249 48,243 48,251 Per common share amounts (basic and diluted): Net income (loss) $ 0.13 $ 0.35 $ (0.33) $ (0.28) $ 0.35 FFO $ 1.14 $ 1.11 $ 1.21 $ 1.30 $ 1.30 Normalized FFO $ 1.13 $ 1.11 $ 1.22 $ 1.30 $ 1.20 CAD $ 0.20 $ 0.58 $ 0.78 $ 1.06 $ 0.88

28 OFFICE PROPERTIES INCOME TRUST NON-GAAP FINANCIAL MEASURES AND CERTAIN DEFINITIONS Non-GAAP Financial Measures We present certain “non-GAAP financial measures” within the meaning of applicable rules of the SEC, including NOI, Cash Basis NOI, EBITDA, EBITDAre, Adjusted EBITDAre, FFO, Normalized FFO and CAD. These measures do not represent cash generated by operating activities in accordance with GAAP and should not be considered alternatives to net income (loss) as indicators of our operating performance or as measures of our liquidity. These measures should be considered in conjunction with net income (loss) as presented in our consolidated statements of income (loss). We consider these non-GAAP measures to be appropriate supplemental measures of operating performance for a REIT, along with net income (loss). We believe these measures provide useful information to investors because by excluding the effects of certain historical amounts, such as depreciation and amortization expense, they may facilitate a comparison of our operating performance between periods and with other REITs and, in the case of NOI and Cash Basis NOI reflecting only those income and expense items that are generated and incurred at the property level may help both investors and management to understand the operations of our properties. NOI and Cash Basis NOI The calculations of net operating income, or NOI, and Cash Basis NOI exclude certain components of net income (loss) in order to provide results that are more closely related to our property level results of operations. We calculate NOI and Cash Basis NOI as shown on page 25. We define NOI as income from our rental of real estate less our property operating expenses. NOI excludes amortization of capitalized tenant improvement costs and leasing commissions that we record as depreciation and amortization expense. We define Cash Basis NOI as NOI excluding non-cash straight line rent adjustments, lease value amortization, lease termination fees, if any, and non-cash amortization included in other operating expenses. We use NOI and Cash Basis NOI to evaluate individual and company-wide property level performance. Other real estate companies and REITs may calculate NOI and Cash Basis NOI differently than we do. EBITDA, EBITDAre and Adjusted EBITDAre We calculate earnings before interest, taxes, depreciation and amortization, or EBITDA, EBITDA for real estate, or EBITDAre, and Adjusted EBITDAre as shown on page 26. EBITDAre is calculated on the basis defined by The National Association of Real Estate Investment Trusts, or Nareit, which is EBITDA, excluding gains and losses on the sale of real estate, loss on impairment of real estate assets and adjustments to reflect our share of EBITDAre of our unconsolidated joint ventures. In calculating Adjusted EBITDAre, we adjust for the items shown on page 26 and include business management incentive fees, if any, only in the fourth quarter versus the quarter when they are recognized as expense in accordance with GAAP due to their quarterly volatility not necessarily being indicative of our core operating performance and the uncertainty as to whether any such business management incentive fees will be payable when all contingencies for determining such fees are known at the end of the calendar year. Other real estate companies and REITs may calculate EBITDA, EBITDAre and Adjusted EBITDAre differently than we do. FFO and Normalized FFO We calculate funds from operations, or FFO, and Normalized FFO as shown on page 27. FFO is calculated on the basis defined by Nareit, which is net income (loss), calculated in accordance with GAAP, plus real estate depreciation and amortization of consolidated properties and our proportionate share of the real estate depreciation and amortization of unconsolidated joint venture properties, but excluding impairment charges on real estate assets and any gain or loss on sale of real estate, as well as certain other adjustments currently not applicable to us. In calculating Normalized FFO, we adjust for the other items shown on page 27 and include business management incentive fees, if any, only in the fourth quarter versus the quarter when they are recognized as an expense in accordance with GAAP due to their quarterly volatility not necessarily being indicative of our core operating performance and the uncertainty as to whether any such business management incentive fees will be payable when all contingencies for determining such fees are known at the end of the calendar year. FFO and Normalized FFO are among the factors considered by our Board of Trustees when determining the amount of distributions to our shareholders. Other factors include, but are not limited to, requirements to maintain our qualification for taxation as a REIT, limitations in our credit agreement and public debt covenants, the availability to us of debt and equity capital, our expectation of our future capital requirements and operating performance and our expected needs for and availability of cash to pay our obligations. Other real estate companies and REITs may calculate FFO and Normalized FFO differently than we do. Cash Available for Distribution (CAD) We calculate cash available for distribution, or CAD, as shown on page 27. We define CAD as Normalized FFO minus recurring real estate related capital expenditures and adjusted for other non-cash and non-recurring items and certain amounts excluded from Normalized FFO but settled in cash. CAD is among the factors considered by our Board of Trustees when determining the amount of distributions to our shareholders. Other real estate companies and REITs may calculate CAD differently than we do.

29 OFFICE PROPERTIES INCOME TRUST NON-GAAP FINANCIAL MEASURES AND CERTAIN DEFINITIONS Annualized dividend yield is the annualized dividend per share paid during the period divided by the closing price of our common shares at the end of the period. Annualized rental income is calculated using the annualized contractual base rents from our tenants pursuant to our lease agreements as of December 31, 2022, plus straight line rent adjustments and estimated recurring expense reimbursements to be paid to us, and excluding lease value amortization. Cap rate represents the ratio of (x) annual straight line rental income, excluding the impact of above and below market lease amortization, based on existing leases at the acquisition date, less estimated annual property operating expenses as of the date of the acquisition, excluding depreciation and amortization expense, to (y) the acquisition purchase price, including the principal amount of assumed debt, if any, and excluding purchase price adjustments and acquisition related costs. GAAP is U.S. generally accepted accounting principles. Gross book value of real estate assets is real estate properties at cost, plus certain acquisition costs, if any, before depreciation and purchase price allocations, less impairment writedowns, if any. Gross sales price is equal to the gross contract price and excludes closing costs. Investment grade tenants include: (a) investment grade rated tenants; (b) tenants with investment grade rated parent entities that guarantee the tenant's lease obligations; and/or (c) tenants with investment grade rated parent entities that do not guarantee the tenant's lease obligations. Tenants contributing 52.8% of annualized rental income as of December 31, 2022 were investment grade rated (or their payment obligations were guaranteed by an investment grade rated parent) and tenants contributing an additional 9.9% of annualized rental income as of December 31, 2022 were subsidiaries of an investment grade rated parent (although these parent entities are not liable for the payment of rents). Leased square feet is pursuant to leases existing as of December 31, 2022, and includes (i) space being fitted out for tenant occupancy pursuant to our lease agreements, if any, and (ii) space which is leased, but is not occupied or is being offered for sublease by tenants, if any. Square footage measurements are subject to changes when space is remeasured or reconfigured for new tenants. Net debt is total debt less cash. Percent leased includes (i) space being fitted out for occupancy pursuant to our lease agreements, if any, and (ii) space which is leased, but is not occupied or is being offered for sublease by tenants, if any, as of the measurement date. Purchase price represents the gross purchase price, including assumed debt, if any, and excludes acquisition related costs and purchase price adjustments and allocations. Rolling four quarter CAD represents CAD for the preceding twelve month period as of the respective quarter end date. Total debt represents the outstanding principal balance as of the date reported. Total gross assets is total assets plus accumulated depreciation. Weighted average remaining lease term (or “WALT”) is the average remaining lease term in years weighted based on annualized rental income.

30 OFFICE PROPERTIES INCOME TRUST Washington, DC INVESTOR PRESENTATION Q4 2022 Two Newton Place 255 Washington Street, Suite 300 Newton, MA 02458 OPIREIT.COM