Which former Pokémon city lies beneath the sea in Pokémon Pokopia’s Bubbly Basin?

Cerulean City lies beneath the sea in Pokémon Pokopia’s Bubbly Basin.

Bubbly Basin is an Expansion Pass area presented as a submerged version of Cerulean City. Rising sea levels have left the city at the bottom of the ocean, where Ditto explores underwater trenches and dark seafloor regions.

Access to the area requires the Dive move. Once there, Ditto’s main project is constructing a large underwater sea temple, following a request from the Popplio who introduces the town. The setting extends Pokopia’s rebuilding theme into an environment that differs sharply from the dry Withered Wasteland and the cloudy Bleak Beach.

Cerulean City is one of several familiar Pokémon locations reimagined in the game’s altered world. Saffron City, for example, is represented by the floating Sparkling Skylands, while Fuchsia is associated with the suspicious building involved in Team R’s initiation challenge. Bubbly Basin was introduced as part of the Expansion Pass released on August 5, 2026.