How to Go Scuba Diving in GTA V: 4 Steps (with Pictures) - wikiHow
How to buy scuba gear in GTA Online
The female model for the scuba suit has big male pecs and I find it kind of amusing. Also, no flippers (still not sure if that affects my swimming speed though) :
Scuba Suit | GTA Wiki | Fandom
Scuba Suit | GTA Wiki | Fandom
Rebreather is the poor man's scuba suit. - GTA Online - GTAForums