ABC7 News as at Dock K as school kids took the first of the special walking tours to see the sea lions.
It's to commemorate the 26th anniversary of when the sea lions arrived at the pier. They haven't left since.
They're now a top attraction at Pier 39, but also an important part of the San Francisco Bay's ecosystem.
"They're also a huge part of the bay," said Robyn Grahn with Aquarium of the Bay. "They are the top predators in the bay area itself. They help manage the food web."
The celebration at Pier 39 continues through Monday with walking tours, freebies, and special presentations at the Sea Lion Center.
Click here for details on the anniversary festivities and click here to watch a livestream of the sea lions at Pier 39.