The ability to Dive in Pokémon Poképia, allowing for underwater exploration and construction, is now available to all players through a free update. While the Bubbly Basin DLC is not required, specific quests must be completed, and another move learned, before the Dive feature is unlocked.
Manaphy, also introduced in the free update, is the Pokémon that teaches the Dive ability. However, players must first learn the Surf move from Lapras and complete the "Raise the Environment Level" request in Bleak Beach.
To find Manaphy, players must reach Environment Level 5 in Bleak Beach after downloading the 2.0 update. Upon returning to the Bleak Beach Pokémon Center, Professor Tangrowth will indicate a newly appeared island in the northwest region. Traveling to this island via Surf will reveal Manaphy, who is hungry. After being fed five bundles of seaweed, which can be found on the island, Manaphy will impart the Dive ability. Notably, Ditto can automatically use Dive when submerged in water without any PP cost.
Learning Surf from Lapras involves fulfilling specific conditions. After completing certain requests from Piplup in Bleak Beach, a hint will be given on how to create a Lapras habitat. This requires one large palm tree, four hedges, and two adjacent ocean squares. The habitat must be placed so the elements touch the water. Players should utilize existing large palm trees, as they cannot be planted or moved. A suitable location can be found near where Smeargle is encountered.
Once the habitat is constructed, Lapras will appear and request assistance in cleaning 80 mud spots around Bleak Beach. Mud spots cleaned prior to Lapras's appearance count towards this total. Upon completion, Lapras will teach the player how to Surf.
Raising the Environment Level in Bleak Beach to at least Level 5 is a requirement set by Professor Tangrowth after the "Brighten Things Up" quest. This can be achieved by ensuring Pokémon have suitable habitats, differentiating between those that prefer light and shade. Most Pokémon should have "nice" status habitats, with a few exceptions. Decorating Ditto's habitat also contributes to the Environment Level.