The Lithuanian Sea Museum is situated in the 19th‑century Nerija Fort, heavily damaged during World War II and restored in 1979 for museum use. Covering about 13 hectares, it includes aquarium halls, marine nature exhibits, maritime history displays, and outdoor pools with penguins, Baltic seals, and northern sea lions. Its exhibitions present four ecosystems—freshwater, Baltic Sea, North Sea, and tropical seas - and a rich marine fauna collection featuring corals, mollusks, fish, and marine mammal specimens.

Next to the museum, the dolphinarium opened in 1994 and is home to Black Sea bottlenose dolphins, offering educational shows. The museum also preserves Lithuania’s maritime heritage, displaying historic fishing vessels and operating a traditional wooden boat, the kurėnas, used for ethnocultural expeditions since 2001. Over the decades, it has become a major center of maritime culture in Lithuania, attracting hundreds of thousands of visitors annually.

During reconstruction, the aquarium received an 18‑meter‑long acrylic tunnel where nearly two‑meter‑long sturgeons swim above visitors - one of the most impressive aquarium features in the Baltic region.