Where can I can I get these?

[Torchwatch]

We've seen these before, always in black, always from the front view and never with a brand logo showing.
I'd suggest they have been custom made for photo shoots.
It doesn't really matter what happens at the back, it could be anything from a thong to a full back but it will show a lot of nether cleavage, half your bum will be showing above the suit, and you will experience tunnelling (a visible passage between the suit and your ass crack) as the suit will sit really low.
If you actually dive, kick turn or swim it this suit it would probably slide down your legs, it is purely for show and only from the front.
I think I could make one if I tried.