Located right on Haeundae Beach, Busan Aquarium (SEA LIFE Busan) houses over 250 species in themed zones that take you from local Korean waters through to tropical reefs and deep ocean habitats. The highlight is a long glass tunnel through the main tank where sharks, rays, and sea turtles glide overhead.
The early exhibits can feel a bit dated, but the experience improves as you go deeper. For something more hands-on, you can book a shark dive in the main tank with gear and training provided.
The aquarium sits right next to the Haeundae tourist information office. If you are visiting from Ulsan, it is an easy day trip by KTX or intercity bus.