A four-story commercial building tucked between Fisherman's Wharf and North Beach could soon trade office cubicles for apartments. The property at 2310 Mason Street, owned jointly by two labor unions, is the subject of a newly filed request that outlines three possible paths to turning the aging structure into housing, ranging from 11 to 15 units.
According to San Francisco YIMBY, the site sits at the corner of Mason and Vandewater streets, just over two blocks from Joe DiMaggio Park and about three blocks from the waterfront Embarcadero. The building dates to 1968 and currently holds three floors of commercial office space above a 12-car garage, according to the same filing. My My Ly Architects is listed as responsible for the application and design.
The property is co-owned by United Educators of San Francisco and the National Association of Letter Carriers Golden Gate Branch 214 Building Corporation, per the filing reviewed by the outlet. UESF is a labor union representing roughly 6,500 San Francisco Unified School District educators, paraprofessionals, and school staff, according to United Educators of San Francisco. The union recently ratified a new contract with the school district in February following a four-day strike, a saga Hoodline detailed in its earlier coverage of the deal.
Three Different Blueprints on the Table
The conceptual plans, published by the San Francisco Planning Department, sketch out three distinct scenarios. The smallest version would convert the top three floors into 11 housing units while retaining the ground-floor parking area, the filing shows. A 14-unit version would spread housing across all four floors and considers adding a corner retail shop, while the most ambitious 15-unit plan also fills every floor with housing.
Branch 214, the building's other owner, represents nearly 1,987 postal workers in the San Francisco area and reported $1.62 million in net assets in 2025, according to the Center for Union Facts. The union operates as a tax-exempt labor organization occupying office space on the building's third floor, per that same record. No estimated timeline for the project has been established, the filing notes, and the request itself is explicitly not a preliminary application or permit filing — it's an earlier-stage step in the process.
A Citywide Push to Turn Empty Offices Into Homes
The Mason Street filing lands amid a broader wave of incentives San Francisco has rolled out to make office-to-housing conversions pencil out financially. Mayor Daniel Lurie signed legislation in June 2025 establishing the Downtown Revitalization Financing District, which lets qualifying conversion projects collect 30-year property tax-funded incentive payments, according to the City and County of San Francisco — legislation Hoodline covered when it was signed into law last year.
The city has layered on additional relief since then. Legislation adopted in April 2025 under Board File 240927 waives inclusionary affordable housing requirements and development impact fees for eligible adaptive reuse projects, a move San Francisco Planning projects could save developers between $70,000 and $90,000 per unit. Separately, voters approved Proposition C in March 2024, waiving the city's real estate transfer tax on qualifying commercial-to-residential conversions that secure planning approvals before 2030, up to a cumulative 5 million square feet citywide, according to SPUR.
Those financial carrots come as San Francisco's office market shows signs of loosening. The citywide office vacancy rate dropped to 29.2% in the second quarter of 2026, down from a record peak of 36.7% in early 2025, according to CBRE. That improvement has been driven largely by expanding artificial intelligence companies, the firm notes, while lower-floor commercial space in older buildings like 2310 Mason Street remains difficult to lease.
Part of a Growing Wave of Small Conversion Filings
2310 Mason Street isn't an isolated case. Project sponsors filed adaptive reuse plans in July to convert commercial office space at 575 Sutter Street near Union Square into 12 residential units, the report notes, while developers filed preliminary plans this month to convert 150 Hayes Street into 104 apartments under streamlined city procedures. Hoodline also reported on a similar shift near the waterfront in May, when an Academy of Art property sale near Fisherman's Wharf drew a housing-hungry buyer.
The building's zoning capacity got a further boost in January, when Mayor Lurie's Family Zoning Plan took effect, expanding allowable residential height and density limits across city neighborhoods to unlock capacity for an estimated 36,000 new housing units — though high construction and financing costs continue to slow development timelines citywide, per San Francisco Planning.
Whether the unions intend to build out the housing themselves or simply entitle the property to boost its resale value remains an open question. The 9,974-square-foot building, which sits on a roughly 0.1-acre parcel, was also listed for sale on LoopNet in July for $3.5 million as an owner-user or redevelopment opportunity featuring the existing 12 garage parking spaces. San Francisco YIMBY notes that project review requests like this one precede formal permit applications, and that high construction and interest costs remain a key hurdle for small-scale residential conversions even with the city's favorable zoning and fee waivers.
