What to wear

What tri distance are you considering?

I always seem to be the dissenting voice on this....honestly, I find that a one piece suit, IF it fits properly, is more comfortable than a two piece. One doesn't have to worry about the top riding up to display more skin than desired, or flapping around on the swim (particularly a problem for tall or long-waisted people or those with a small waist). If the suit has a front zipper, then access for bathroom stops is really no more difficult than untying a drawstring on tri shorts--I find it a lot easier. I also do a lot of my races in the ocean, and at times am swimming against a strong current--similar effect to pushing off the wall in a pool--a one-piece works much better for those conditions.

That being said, for a beginner, a tri top and shorts are probably more practical, since the pieces can be used for a variety of workouts (biking, running, gym sessions), unlike a one-piece, which is basically good only for triathlons and open-water swimming, unless you like riding/running around town in what looks like a bathing suit with longer legs.

To my knowledge, for USAT or WTC races, capris wouldn't be legal in a swim that didn't allow wetsuits; anyway they would not be comfortable on the swim. I think suits are not supposed to go past elbows or knees. (Maybe there are exceptions if it's for religious or medical reasons? Not sure.) You do see people who do the swim in a swimsuit and then put on bike or run shorts or capris for the ride and run. But I haven't heard of capri-style tri shorts. Biking capris might have too much of a pad to be comfortable on the run; run capris would lack padding for the bike. The latter might be okay for a short race like a sprint, but I can testify from my first tri that wet swimsuit plus another layer over the top plus biking often equals painful chafing, even in a race in the 90-minute range.

Tri shorts come in a variety of lengths, and some are quite modest. I prefer ones that cover most of my thighs, for modesty, sun protection, and compression that seems to help prevent hamstring cramping. Unless there's a religious or health imperative to cover up all the way to mid-calf, I recommend investing in a comfortable tri top and shorts, or a one-piece, with longer legs.