You could try using Victoria 3.0, a free figure from DAZ.

http://www.daz3d.com/

Then you could do the swimsuit as a second skin by going into
Poser's material room, selecting the body parts you want
to be the swinsuit, and changing the diffuse color to blue.
If you want a male figure, Michael 3.0 is also free and
can use the same colors as Victoria 3.0.