I wear a tri 'bikini-style' top underneath my tri suits to keep the girls in.  I have a TYR maxback and 2XU Comp (my favorite).  I like the 2XU a little more because there is little/no chafing and the cut is a little higher on top, so when I start running I know I won't have wardrobe malfunction.  Also, I only say tri-specific because the wicking is better and less chafing.  I will even wear my tri tops on my training workouts because of comfort.

You are SO not alone, as I have three weeks until my 3rd tri and am tired of wearing my sturdy running bra and running shorts while I swim (I keep this combo on for all three events).  So, can you all clarify:  You wear a tri outfit for all three events with the bra underneath?  I am very ready to upgrade my equipment and need help.  I am a 34DD and cannot run in just a tri suit alone.

Thanks!

if you're managing an open water swim. Some of my sports bras were smaller slash in the front & conceived more pull, even under a tri top. Other sports bras have wider material all round and thus contain water long after you've left the bathe segment. Also gaze at the slash of the edges & how reduced it is seated under your arm, you could have chafing with a wetsuit.

I always wear a sports bra under my tri-suit. The girls would have a dance party if I didn't. Many women do as well. Just do some "test runs" with some sports bras to see what works best for the tri-suit you'll be wearing and you're good to go!