The Steinhart Aquarium, Golden Gate Park
The Steinhart is part of the California Academy of Sciences, in the park, on the Music Concourse opposite the de Young. It has been there since the Academy's new building opened in 2008, and before that it had occupied the same site for most of a century — the downtown address that still circulates belonged only to the handful of years in between.
It holds over a thousand species. The centrepiece is a living coral reef tank of some 800,000 litres, and the rest divides between a twilight-zone display of deep-reef animals that most aquariums cannot keep, a colony of African penguins, a tide-pool section with animals that can be touched, and an eel collection that is better than it has any need to be — moray alongside wolf eels, which reach a little over two metres.
The practical argument for it over the other two is that the ticket is not only for the aquarium. The same admission covers the Morrison Planetarium, the four-storey Osher Rainforest and the natural history galleries, with close to sixty thousand animals in the building altogether. It is a full day rather than an hour, and it is the best value of the three by some distance. The rest of the Academy is covered under science museums and the zoo.
Aquarium of the Bay, Pier 39
The name is Aquarium of the Bay, not Aquarium by the Bay, which is how it is often rendered. It opened in April 1996 as UnderWater World and took its present name after being remodelled in 2001.
Two acrylic tunnels run for about 110 metres in total through tanks holding roughly 2.7 million litres of filtered water drawn straight from San Francisco Bay, with a moving walkway through them. There are around 24,000 animals from more than two hundred species.
What distinguishes it is that almost everything in it lives in the bay or just outside the Golden Gate. There is nothing tropical and no spectacle: sevengill, leopard, soupfin and swell sharks, bat rays, skates and rockfish, moray eels, anchovy shoals, white sturgeon, moon jellies, Dungeness crab, and river otters. For a visitor who has spent the morning looking at the water from a pier, an hour spent looking at what is underneath it is a better use of time than it sounds.
There is a caveat, and it should be stated rather than buried. The Association of Zoos and Aquariums revoked the aquarium's accreditation in May 2024, citing deteriorated equipment and inadequate control of tank water temperature; the aquarium's own staff said at the time that a substantial proportion of the animals needed to be housed elsewhere. It remains open and operating. Whether that matters is a judgement for the visitor, but it is the sort of thing worth knowing before a ticket is bought rather than after.
Monterey Bay Aquarium, which is not in San Francisco
Monterey is about 120 kilometres south — roughly two hours by car in reasonable traffic, and longer by coach. Treating it as a San Francisco attraction is the mistake that ruins it. It works as a full day out of the city, or far better as a stop on the drive down the coast, and it does not work as an afternoon.
It is also, by a considerable margin, the best of the three and among the best aquariums anywhere. The kelp forest tank runs the full height of the building with real surf at the top of it. The jellyfish galleries are the reason the place is photographed. The Open Sea tank holds tuna and sunfish and sardine shoals at a scale nothing else attempts. Sea otters are rehabilitated on site, and wild otters and harbour seals are frequently visible from the decks without any tank at all.
It is a research institution as well as a visitor attraction, and most British visitors have already encountered its work without knowing it — the Seafood Watch sustainability ratings originated there.
The white sharks, which older accounts get wrong
Monterey is widely said to have kept a great white shark, often with the detail that it was displayed for almost two years. That is not right, and the real story is more interesting.
Between 2004 and 2011 the aquarium held six juvenile white sharks. The first, a young female caught accidentally in commercial fishing nets in 2004, stayed 198 days before being released back into Monterey Bay. Close to a million people saw her, and that 198 days remains the record for a white shark in captivity anywhere in the world.
The sharks that followed did considerably worse. Several were released early because they would not eat. In 2013 the aquarium announced it would not attempt it again, citing pressure over the species' conservation status.
No aquarium anywhere displays a great white today, and the reason is simply that the species does not survive confinement — an open-ocean animal that must keep swimming forward does badly in any tank yet built. Any attraction claiming to have one is not telling the truth.
The Pier 39 aquarium sits at the end of Fisherman's Wharf; general practicalities for the city, including the weather that catches visitors out, are on the San Francisco page.