Model is wearing is wearing a size S.

Top size depends on the style and look you like. 

Example: You may be a C/D cup which is normally a size M, but desire less coverage- a size S would suit this look. 

If you have a wide back please size up.

For Baby Pink/Silver 2 piece & Electric Blue one piece: Sizes run small meaning: SMALL is really a XS, MEDIUM is really SMALL, LARGE is MEDIUM, and so on. 

For Black & Red one piece: Sizes run true to size: SMALL is S, MEDIUM is M, LARGE is L, and so on.