I am a size 34C and ordered a size M which is my usual size in most sports bra brands. I would usually assume a size M is the equivalent of a size 10/12 but this fits like it's a size 6/8 - it's impossible to get my arms through it whilst trying to get it over my head! I am so disappointed there is no bigger size as the fabric is very good quality.

I’d advise anyone to get the next size up. There wasn’t enough stretch in the material, I couldn’t get it on at all, it was far too tight. I compared it to another sports bra I own, the sizing was almost identical but without the stretch it was just far too small. Unfortunately its out of stock in the next size up, so can’t really say how good it is during activity! 

I LOVE the back of this! I got a size S, my normal size. I'm happy with the fit, but the band is a little tight when putting it on. once it's on its comfortable and pretty supportive. the material has a cotton feel and did have a few small sweat patches in places after my run. Very comfortable during my run, it didn't feel tight and I had good movement in it.