Major closures through the Panhandle, Golden Gate Park, and along Ocean Beach, beginning 6am. All roads should be open by noon.
From
https://sanfranciscohalfmarathon.org/race-information/transportation :
Panhandle
7:15 a.m. to 10 a.m.
Oak and Fell Streets will be closed from Broderick to Stanyan.
Broderick and Baker Streets will be closed between Page Street and Hayes Street (local access for residents will be allowed up to Fell or Oak). Masonic and Stanyan Streets will be closed between Haight Street and Hayes Street (local access for residents will be allowed up to Fell or Oak).
Use Divisadero for through traffic north or south.
Golden Gate Park6 to 9:30 a.m. — All park roads east of Transverse
6 to 11 a.m. — All park roads west of Transverse (JFK from Great Highway to Chain of Lakes will be closed until 12:00 p.m.)
Use Crossover Drive for through traffic north or south.
Great Highway/Sunset Dunes8 a.m. to noon
Full closure both directions on the Great Highway between Fulton St. and Lincoln Way. Sunset Dunes closure remains in effect.