I had good luck finding smaller unpadded sports bras at Academy. TomboyX sells compression tops that won't get you flat as a binder but I like them because they are safe to work out in. They look more on the sports bra end of the spectrum IMO. I also use kinesology (sp?) tape on occasions like swimming.

(Edit: I'm naturally smaller chested)

MTF here, so I don’t have full context/wisdom. I’ll try to articulate what I’ve gathered from my trans masc friends that aren’t on this platform.

I think it depends a bit on your chest size? If you’re on the smaller side and need something incognito you could probably get away with KT tape or other skin/body safe tape. Generally be a bit careful with tape. Pulling at skin too hard can cause irritation and even tears/splits. Skin can react to adhesives if left on for too long, things like that. A quick web search can go a long way here for checking out what works well.

For bigger chest sizes my understanding is that a good full coverage sports bra is the best option. Maybe shop a size down if you can stand it. Please do be careful though, too tight and you can hurt yourself. I know someone who would sometimes tape and use a sports bra to help position things so the sports bra did more flattening than holding up.

In my own itty bitty titty experience I have a bra from girlfriend collective that is fairly low stretch and I bought a size down in case I feel the need to be REALLY stealth mode.

Sorry to invade y’all’s space a bit, just an area I happen to have a bit of knowledge in! Best of luck! Stay safe! 💜 🏳️‍⚧️ ✊

I actually don't wear bras or binders. Ever since I encountered a trans guy who didn't wear binders but not bras either, just a shirt (optional) underneath and a hoodie and I came out as unlabeled but definitely trans and not cis, I didn't wear bras. Plus, I heard that binders can be uncomfortable, and I value comfort.

When I started binding I used a backwards bra, though it's not the most comfortable or aesthetic option. There are binders that can pass as sports bras, if you want something you can sneak under the radar.

consider compression tops, or a sports bra you can wear backwards