Incredible sight at San Francisco’s iconic Pier 39

Tourists have been treated to an incredible and rare sight at San Francisco’s iconic Pier 39.

Tourists at San Francisco’s iconic Pier 39 have been treated to an incredible sight of more than 1000 sea lions hanging out on the docks.

The California sea lions have been a tourist attraction there for decades but not all visitors get so lucky, with the animals coming and going.

This is the largest group in 15 years.

California sea lions lounge on docks at San Francisco’s Pier 39 on May 5. Picture: Justin Sullivan/Getty Images/AFP

The sea lions have been a top attraction at Pier 39 for nearly 35 years. Picture: Justin Sullivan/Getty Images/AFP

Pictures show the sea lions taking over the barges, but tourists are warned they will probably smell them or hear them barking before they see them.

“When they’re all together like this, they’re much more energised,” Pier 39 harbourmaster Sheila Chandor told the Today Show on NBC.

“People describe it as a giant frat party right now.”

This is the biggest group seen in 15 years. Picture: Justin Sullivan/Getty Images/AFP

The surge in the number of sea lions is because of large schools of anchovies in the bay. Picture: Loren Elliott / AFP

Sea lions were first spotted hanging out at the pier after the Loma Prieta earthquake in October 1989 and in November 2009 the number of sea lions hit an all-time record of 1701.

The surge in number of sea lions in the area is due to large schools of anchovies in the bay waters that will allow them to fuel up before mating season.

They are expected to be around for a few more weeks before migrating south to the Channel Islands.

The steady food supply is making them more active and playful, making a great sight for tourists.

If you can’t make it to San Francisco, the pier also runs a live sea lion webcam that you can watch online.