The Oceanic Museum (Japanese: うみのかがくはくぶつかんOcean Science Museum) is a building located in Slateport City. In Ruby, Sapphire, and Emerald, the player must go there to give Captain Stern some parts from the Devon Corporation. There are ten people inside the building. A sign outside the museum reads:
"The endless sea sustains all life." OCEANIC MUSEUM
The player must pay an entrance fee of $50 to enter the museum. One of the Team MagmaR/Team Aqua GruntsSE visiting the museum, the same one that the player had beaten in Petalburg Woods and Rusturf Tunnel, gives the player TM46 (Thief). The Grunt will stay in the museum until he gives the player the TM and runs off after giving it to them.
The first floor contains information about the sea in the form of seven exhibits. There is also a reporter who asks the player to tell him a story about Pokémon. This report will later be aired on TV.
On the second floor, the player will encounter more members of the villainous team. Additionally, this floor has nine exhibits which include models of the Hoenn region and the cruise ship S.S. Anne.
In Pokémon Emerald, Scott will speak to the player once he or she leaves the museum to find out who defeated Team Aqua.
The museum can be entered free of charge before Team Magma or Team Aqua leave, as the reception believes that the player is part of their group. However, it only works if the player lacks the $50 fee, which will prompt the receptionist to believe that the player is part of either Team Magma or Team Aqua.
In Pokémon Ruby and Sapphire, the upper floor of the museum has water samples from both Kanto and Johto. This was changed in Emerald; instead, they are labeled Water Sample 1 and Water Sample 2.