How to take BART + Muni Rail to Chase Center
If you are coming from the East Bay or the Peninsula, take BART to Powell St. Station and follow signage upstairs toward the Muni station. Once you exit the fare gates follow the "T" Muni signs to transfer to the Muni T Third trains at Union Square Station. Screens located above you will show the next coming Muni Train. Hop on a Southbound T Line train heading toward Sunnydale. Enjoy the ride
Watch this video to see BARTy take BART + Muni Rail to the Chase Center.
How to take BART + Muni Bus to Chase Center:
Take BART to 16th st Mission station and transfer to special Muni 78X service. This route only runs when there is an event at the Chase Center, connecting ticketholders with the 16th Mission BART station. Pre-event service starts about 2.5 hours before the start of the event or game. Post-event service starts after the event or game has ended and continues for about an hour after.

Check out the below rider guides, which explain how to get to some of the Bay's favorite venues.
Find other rider guides here: Chase Center | Levis Stadium | Oakland Arena | Oakland Coliseum | Oracle Park | Moscone Center