Ash and Max visited the Oceanic Museum in The Spheal of Approval, where they met Captain Stern, who was analyzing a heat-affected rock sample from the ocean floor. During their visit, Team Magma tried to steal the stone sample, though Ash and Captain Stern intervened. During the squabble, the sample broke into two pieces, with Team Magma escaping with the larger portion. Captain Stern was left with the smaller fragment, though it was still sufficient enough for his research.
Marius often frequents the museum because of his passion for research and Water Pokémon. His favorite exhibits are the models on display, including those of a submarine and several Pokémon.
The museum's theme is a remix of the song heard on the S.S. Anne.
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.