What have you worn
 

With the post on what suits people have seen at pools or lakes... what is the smallest tightest suit you have worn at a beach, pool, lake, etc (not at home)?

smallest/tightest
 

Sounds good to me. Mine was at the beach in a superb 1" light blue Jantzen.
The model has long gone and the name of the fabric I have forgotten but it was a great fit with what I recall as a tiny honeycomb texture.

The length of a suit at the hip is limited by the width of the elastic used. The waist elastic tends to be 0.5" 12mm, while the leg hole elastic is 0.25" 6mm. Using thinner elastic than this would make a suit that would either fall off or cut into you.
Although the waist and leg elastic may touch at the hip they shouldn't be allowed to overlap as this would cause a bulge and spoil the smooth look of the suit. The minimum hip length of a brief style swim suit is therefore 0.75" 18mm. Even thongs obeys this rule.
Choosing a string bikini allows you to have only a 0.5" 12mm elastic "string" at the waist, on a suit that is comfortable and practicable.
G strings use narrower elastic but you are unlikely to want to wear for long as they tend to be rather uncomfortable.

I tend to wear 2" 3cm Speedos in the pool or public beach, a 1" bikini on a quiet beach and a string bikini or swim thong in the dunes. The objective is always to "push the envelope" to wear as little as is appropriate in any location without upsetting anyone. Sometimes a person that finds me wearing a skimpy suit in a secluded sunny spot in the dunes will ask if they can join me.