HOLY STRETCH AND COMFORT - you will not want to go back to a regular bra after wearing these. These are not padded, but are thick enough to not need layered unless you like the additional support. Get your usual shirt size OR sports bra size, they are stretchy enough to make the sizing pretty flexible. The reviews on these say will fit anywhere from an A cup to a DDD!
Auriele is wearing the L/XL for reference.