What you need to do if this is your problem is to draw the eye away from your sticking out bones, and wear a swimming costume that will camouflage your bones.
In figure A you see the problem with wearing a bikini. It will accentuate your jutting ribcage, and bony hips. Worse still the skimpy top calls even more attention to the problem.
What you need to wear is a one piece suit that will hide your sticking out bones. Geometric designs, (as in figure C) will help to fill out a straight up and down figure particularly if they have angles,
It is a good idea to avoid anything totally strapless. You can also use added frills or decoration to help make the most of a slender shape.
In figure B you see a feminine and flattering one-piece costume, which is gathered softly at the bustline to fill out a small bust. A top which knots in the front would also help to make the most of a small bust. A lighter halter top with darker bottoms will help to super-size your breasts.
If you are as straight as a surf board, wear a belted suit to give you a waistline. You could also consider swim shorts and a tank top which covers your tummy.
It is not easy to find a perfectly fitting swimsuit, so whenever you do find one, buy several in different (but harmonising colours). You can then mix and match them for extra pizzazz.
Make sure you have the right cover up for the beach or pool. A kanga is a piece of cloth about 1.5m by 1.2m and it can be worn as a dress, a skirt, a sarong, or even as a pair of trousers. A terry towel mini or knee length skirt is a good cover up, and can be worn with a hooded top or fitted tank top.
A wide brimmed straw hat is a must have, as well as sunglasses, a beach bag and a brightly coloured towel.