Bubbly Basin
Formerly: Cerulean City (submerged)
Kanto’s old water city, underwater
Bubbly Basin is the Expansion Pass’s area — a submerged former Cerulean City, released August 5, 2026 alongside a free 2.0.0 update that added the Dive move game-wide. It’s unlocked after completing Bleak Beach’s “Raise the environment level!” request.
Getting in
Speak to Professor Tangrowth outside Bleak Beach’s Pokémon Center, then head to an island to the north to find Manaphy, who teaches Ditto to Dive. Return to the Pokémon Center afterward and Popplio is waiting — befriend it to open up a Basin-specific Pokédex page, since it needs to accompany you to unlock the area’s gate. That gate sits underwater to the west of Bleak Beach; Dive down to it to enter Bubbly Basin itself.
What’s confirmed here
The DLC adds 50 new Pokémon across 36 new habitats, mostly Water-types absent from the base game. Confirmed spawns include Corsola and Shellder together in a habitat built from Seabed Tall Grass ×4, Small Coral ×1, and Tall Coral ×1, plus Staryu and Horsea elsewhere in the habitat list. A distinct subset of Ancient Artifacts — Sunken Large Lost Relics (a Windup Inkay, a Chimecho wind chime, a Gyarados fountain, and more) — is exclusive to this area; see the Collectibles page. Other Bubbly Basin-specific collectibles referenced in source material include pearls and treasure maps.
Still unconfirmed
This guide hasn’t verified Bubbly Basin’s own Environment Level milestones or Professor Tangrowth’s role (if any) once inside the area itself, nor mapped out habitats for most of its 50 new Pokémon. Treat this page as a work in progress relative to the base game’s five areas — see the Expansion Pass note under “Beyond day one.”