These are a great altertnative to bikinis and one pieces. They don't have the same problems that one pieces have---sagging, baggy fit, etc... and they also cover your stomach much better than a bikini.
Here are some very cool tankinis that you can get from Macys. Most of these come in multiple colors.
In reality, if youre looking for a bikini that will hide belly fat, it's simply better to get a tankini. They give you the flexibility of a bikini and the coverage of a full suit.
If you're looking for a more casual style, then this is an awesome choice. If you have a but of a tummy, and are looking for a tankini or bikini to hide belly fat then this will work really well. It's like a shirt, but it won't get clinglly in the water. It shows some skin, but you can adjust it to cover what you like.
