At about 5:30 p.m., 300 to 400 protesters were peacefully marching outside AT&T Park's Willie Mays Plaza, according to police.
Police said about 40 to 50 protesters entered AT&T Park lawfully with purchased tickets.
The protesters then staged a "sit-down" strike near section 119 of the stadium, according to police.
Police explained to protest organizers that they were in violation of AT&T Park/Giants fan code of conduct, which applies to anyone who attends a Giants game at the park.
Patrons in violation of the code can be asked to leave the premises or are subject to arrest, police said.
Ten protesters participating in the "sit-down" strike refused to leave the park and were arrested.
All other protesters were escorted off of the Giants property without incident, according to police.
The ten protesters were cited for trespassing and released from custody outside AT&T Park. (Bay City News contributed to this story.)