The Seaside Aquarium has been on the Promenade since 1937, making it one of the oldest aquariums in the Pacific Northwest. It is small and resolutely unglitzy — no overhead walkways or whale sharks, no corporate branding, just tanks of Pacific marine life and a outdoor harbor seal pool where you can buy a small bucket of herring and feed the seals directly. The seals are loud, enthusiastic, and completely comfortable with humans.
The indoor exhibits cover local marine species: rock fish, crabs, sea stars, and the occasional octopus. The building is older and the signage is not state of the art, but there is something appealing about a place that has been doing the same thing for nearly ninety years without needing to reinvent itself. For families with young children, the seal feeding alone is worth the modest admission price.