When the venue requires a swimsuit, I wear a blue
g-string thong. The pouch is just large enough to cover the required
parts while the waistband and back-strap are about a ¼" (5mm)
Occasionally, the venue doesn't allow a suit that small; then I wear a thong. It may be one of several, but it's usually blue and will have a waistband of an inch or less with a little triangle at the top of the back side. (A few years ago, because of the name recognition, I'd wear a Speedo® brand thong. But, it's now discontinued. Even then, it had too much fabric!)
When the area is really stuck up, I'll wear a bikini. A few years ago, it would have been a Speedo® brand. Now, it's the "Kiniki Tan Through Swim Micro", which has just enough fabric to keep people from having any serious complaint. With SPF 8 lotion the resulting suntan is the same as if I had worn no suit!
When making a trip to use a beach or pool, if the venue does not allow a bikini, which is the world-wide standard for a men's swimsuit, then I choose another location. If the place is so stupid in this regard, they are not going to get my tourism money!
Usually, I don't put on a cover-up to and from the beach. If I do, it's never more than the Kiniki suit. I'll wear flip-flops when the sand is going to be hot. But no shirt or shorts or socks.
I enjoy communicating with people about adopting the "thong-wearing" lifestyle. It doesn't matter to me whether your are male or female, straight or gay, or your creed or color. If you want to email, it's bluethongguy at gmail.com - be sure to put something about thongs in the subject, or you'll get reported as a SPAMmer!