Festivities run through Sunday evening and include a parade, hundreds of exhibitors, and more than 20 stages hosting the biggest names in entertainment.
PHOTOS: 2015 SF Pride celebration
The celebration this weekend is expected to be even more festive than past years after the U.S. Supreme Court's decision Friday to make same sex marriage legal in the United States, according to the San Francisco Travel Association.
Sunday's events begin with the parade at 10:30 a.m. along Market Street from Beale Street to Eighth Street, according to SF Pride.
DETAILS: 45TH Annual San Francisco Pride Celebration & Parade
The annual Dyke March arrived in the Castro District for Pink Saturday celebrations, a preview of Sunday's 45th Pride Parade which could be one for the record books. "We're expecting our largest parade ever. I can say we're close to 250 contingents, more floats than we've ever seen," Pride Parade Executive Director George Ridgely said.
The pride festival party is at Civic Center. This year's pride theme is Equality Without Exception.
"This one came running in when I was asleep yesterday and said 'we can get married wherever we want,"' Gigi Chijate
The De Jesus family brought their two daughters to celebrate on Saturday. "I think if we're allowed to get married everyone else should be, what's the difference?" Claudia De Jesus said.
There was a champagne christening for the iconic Pink Triangle, high atop Twin Peaks. Saturday's dedication was more than a yearly ritual, it was historic. "We have a law across the land. Now we join Ireland and 18 other countries to move this movement forward," San Francisco Mayor Ed Lee said.
The U.S. Supreme Court ruling granting marriage equality for all is amazing and surreal for Patrick Carney who created the giant Pink Triange 20 years ago. "The Supreme Court is a marvelous way to start pride weekend, but we need to remember where we came from," he said.
PDF: Supreme Court opinion on same-sex marriage
PDF: Supreme Court summary of Obergefell vs Hodges
The Pink Triangle was once used by the Nazi's to identify and shame homosexuals during World War II and it's now a symbol of pride.
More than 240 organizations will participate in the parade.
Sunday from 2 to 5 p.m. SF Pride is hosting a VIP party at City Hall. Tickets can also be purchased here.
Other events on Sunday start at 11 a.m. in Civic Center Plaza and go to 6 p.m., organizers said.
The two-day Civic Center celebration will have more than 20 stages and venues and nearly almost 300 exhibitors.
"For 45 years the annual Pride event in San Francisco has been a catalyst to build community, celebrate diversity, and unite to take on those who would deny us our freedoms locally and abroad. Our theme Equality Without Exception is timely; queers and allies alike need to vote and stay vigilant," SF Pride board president Gary Virginia said in a statement.
SF Pride is a nonprofit responsible for producing the celebration and parade.
The celebration also includes speakers Alicia Garza, who started the #BlackLivesMatter Movement and Kate Kendall, who leads the National Center for Lesbian Rights, organizers said.
Entertainment is planned too. Grammy-nominated rock/electronica band Shiny Toy Guns will play on the main stage Sunday, according to organizers.
BART officials said to help participants get to the parade they will be running more trains Sunday, which will be the length of weekday commuter trains.
Golden Gate Ferry is also offering more trips than usual Saturday and Sunday from the Larkspur Ferry Terminal. Ferry officials are asking travelers to purchase tickets in advance.
Pride organizers are asking attendees and spectators to donate $10 at the entry gates to support SF Pride's mission and to support the celebration's nonprofit partners, according to SF Pride.
"As with every Pride event, this year serves as the perfect opportunity to commemorate the struggles our community has faced, celebrate the victories we have won, and shed light on the barriers we have yet to dissolve before we reach full equality and fair treatment for every member of our community," Pride executive director George Ridgely said in a statement.
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For more details about the 45th annual San Francisco Pride celebration and parade, click here.
The Associated Press contributed to this report.