My wife and I snorkeled out far off shore on our honeymoon in Grand Cayman. We then proceeded to have a little fun without the bathing suits. It was awesome. Luckily there were no critters around to byte on pieces and parts. I wouldn’t be apposed to a similar excursion with scuba gear.
Side note: My wife dives a DiveRite Transpac in a string bikini with no crotch strap. No chafing.