There really isn't any public park space to eat a brought lunch. I'd eat before coming or budget for eating out while in the city.
There are great restaurants to eat around the area but no available spots to eat food there. The Westfield Mall is a BART stop away from here. You can go there to eat and walk around before the show.
During the day you can bring your lunch and have it around UN Plaza or Civic Center Plaza but I wouldn't advise doing so if you're going for any evening shows.
Civic Center Plaza!!!
No, don't bring a lunch to the Theater.
No, not any public spot that is good for eating. There are nice places close by though.
For the afternoon shows, on Wednesday and Sunday, there are some luch tables set up at farmer's market. You are allow to bring soft drink and sandwiches into the theater before the show.
Not really, as everyone else has suggested, you should eat either before or after the show.
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