I have put together a collection of mastectomy tankinis that are ideal for ladies who have had breast surgery, and now wear a prosthesis. I think these provide the ideal balance between modesty and a great looking swimsuit.  They are pretty, and have a higher neckline for additional modesty.  I now have several exclusive lines from Jamu - but stock is limited so when they are gone they are gone.  Well worth a try if you are looking for something special.  They are all pocketed and will securely hold a breast from. For swimming, either in chlorinated or salt water, I do recommend the use of a swim form. These are quick drying, lightweight prostheses that are highly chemically resistant.