The home opener is a special game for players and fans.
"You can't explain it," said fan Robert Srabian. "You feel it in your bones in your body and your heart."
Fellow fan Chris Archuleta added, "For us, we've been coming to Opening Day as long as we can remember."
PHOTOS: San Francisco Giants celebrate Opening Day at AT&T Park
It's a tradition for many. Fans say it's important to show their support as players make their way back to the ballpark for the first time since they played in last year's World Series. The 16th season is starting off with a celebration.
"Opening Day is always a big day," said SF Giants spokesperson Staci Slaughter. "In my house it's a holiday. It's really special to be back here to raise the third championship banner."
Crews worked countless hours behind the scenes to prep the field and put up signs.
"We probably have a record number pieces of bunting out," Slaughter said.
Fans came from all over the Bay Area and from across the state.
One man named Robert from Fresno is holding his family reunion at AT&T Park. He's been supporting the team since 1953.
"You can't watch it on television and get the same experience," he said. "The crowd just makes it better."
The energy is contagious. Some fans braved the morning chill to wait outside for autographs.
Fans out early this morning trying to get autographs from the players pic.twitter.com/jb9wwbHyr6— Janet O (@JanetONews) April 13, 2015
"When players come in hopefully we get fortunate to get their autographs and stuff," said a fan named Chris. "
While others are already stocking up on new Giants gear, the 2014 championships shirts are expected to go fast.
But above all else, fans say it will be emotional to not only see the 2014 championship banner being raised, but saying goodbye to a SF Giants icon.
"The downside is going to miss Lon Simmons from being here," said Robert.
The longtime Hall of Fame broadcaster was honored at Monday's game. The 91-year-old died just over a week ago following a long career for not only the Giants, but also the Oakland Athletics and San Francisco 49ers.
The team also honored Bridget Klecker during a moment of silence before the game. Klecker, a longtime Giants fan, was hit and killed during a police pursuit Friday night at California and Kearny streets in San Francisco. She was an innocent bystander as three suspected robbers tried to get away from police. Police are still looking for those suspects.
The Giants are glad to be home. A 6-4 loss to the San Diego Padres Sunday left the defending champs with a 3-4 record for the first week of the season. Wil Nieves hit a grand slam off Jake Peavy to pace the Padres.
The orange and black sent rookie Chris Heston to the mound, just the second rookie ever in Giants history to start an opening day. The Giants have won 11 of their last 13 home openers.
The daughters of Lon Simmons threw out today's ceremonial first pitch.
The game started at 1:35 p.m.
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Nothing like the home opener especially after a World Series title! pic.twitter.com/InXZHLa0Ir— Mike Shumann (@MikeShumann) April 13, 2015
Remodeled club house where players will be prepping later , getting suited up pic.twitter.com/H5YRjiS9wJ— Janet O (@JanetONews) April 13, 2015
Bruce Bochy watching the troops warm up. 3 Game losing streak hopes to end today vs Rockies. pic.twitter.com/DRsnujDVcG— Mike Shumann (@MikeShumann) April 13, 2015
It's a banner day for the World Series Champs. Nothing like home opener. pic.twitter.com/RSDZeGK6Z4— Mike Shumann (@MikeShumann) April 13, 2015
The Giants hope to stand tall today vs Rockies in home opener. pic.twitter.com/HU5OmZfOJs— Mike Shumann (@MikeShumann) April 13, 2015
Angel Pagan talking strategy to end a 3 game slide. pic.twitter.com/Vkro30ayuP— Mike Shumann (@MikeShumann) April 13, 2015
No panic in Joe Panik as he warms up his swing. pic.twitter.com/AKX1EUxukH— Mike Shumann (@MikeShumann) April 13, 2015