Verified August 9, 2026. Nintendo pages disagree by region: Singapore, Hong Kong, and UK material describe the August Ver. 2.0 release, while some US storefront and support pages still show August scheduling or October 31 metadata. Check the software version and DLC status on the account and console being used.
Use the reported Dive input as a combination
Start in water after Dive has been learned. Hold B to maintain swimming movement. While continuing to hold B, press or hold L to descend and R to rise. A current community megathread and follow-up help discussion describe the shoulder buttons as vertical controls used during the B-held swimming state. This explains why pressing L alone can appear ineffective.
These button details come from players using the current update, not from a Nintendo control table. Test them in open water away from a gate or low ceiling, where vertical movement is easy to see. If the character still cannot change depth, confirm that the save has actually completed the Manaphy step and learned Dive rather than merely owning the update.
Surf is a prerequisite, but Dive is the underwater tool
Nintendo states that the character must know Surf and have the jumping capability required to learn Dive. Once learned, Dive provides extended, free underwater movement and makes underwater exploration and construction possible. Surf and Dive should therefore not be treated as interchangeable actions: Surf helps satisfy the unlock condition, while Dive is the movement ability used below the surface.
A player asking why Surf would not trigger underwater received two community suggestions: hold B longer and use a smoothie-based Surf enhancement. The second suggestion was not independently confirmed in the evidence reviewed here, and Nintendo does not list such an enhancement as a requirement for ordinary Dive movement. This guide does not present that smoothie suggestion as a necessary fix.
Separate control trouble from progression trouble
If you can move vertically but the underwater gate remains closed, the buttons are working. Return to the entry checklist: complete “Raise the environment level!” at Bleak Beach, finish the Manaphy and seaweed steps reported by players, speak with Popplio, and take Popplio to the marked gate. A community report also suggests using D-pad up when Popplio is nearby but not following.
If you are already inside and a building preview stays red, movement may be the clue rather than the cause. Descend to the seabed and let the character settle before placing. A slightly elevated position can make an otherwise ordinary target invalid according to player reports. A whole-area restriction, by contrast, points toward unfinished local progression rather than a missing Dive input.
Verify version and region before debugging inputs
Nintendo’s regional release information conflicts. Singapore and Hong Kong material describes the Ver. 2.0 content as available from August 5, 2026, and UK material uses an August window. US support still describes an August schedule, while some storefront metadata displays October 31. Confirm that the console shows the update and DLC available for its account region before assuming a control failure.
If the correct version is installed but the reported B-plus-L-or-R combination does not work in open water, record the software version, controller type, control-remapping settings, and exact quest stage before seeking support. Those details distinguish a regional or progression block from a genuine input problem; the current evidence does not establish alternative buttons for remapped or accessibility configurations.