[quote=@RisingRobin]
<Snipped quote by Archangel89>
Actually it’s canon in both the anime and the Pokémon Ranger spin offs that technology exists that lets trainers breathe underwater for indefinite amounts of time (Aqualungs). So long as you have a Pokémon to get you down there, you’d really only need that. Gyarados could just pull you down.


[/quote]
Do those Aqualungs help against ocean pressure I wonder?