When trying to surface on water while swimming to regain air, the level you have to surface to to start regaining air isn't aligned with the level that the first-person camera stops being underwater
From rudimentary testing using teleportation, while not swimming, the height offset relative to the top of the water block where air gain begins is -0.02, and the "submerged level" (level at which the underwater fog effect is applied) is -0.131(1), which aligns with the water texture.
My suggestion would be to lower the level at which air starts regenerating to the same level at where the camera visually submerges underwater
Tntmister
Thank you for your report!
We're actually already tracking this issue in MC-133524, so this ticket is being resolved and linked as a duplicate.
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