Being from Hawai'i I know first hand the unpredictability of wearing a bikini to the beach especially if there are waves. I, personally, go for board shorts and a tankini. They make really cute board shorts nowadays in varying lengths and colors. I'm planning a trip to Disney World this summer and figure the board shorts would be best for the water parks. The tankini holds everything in place. I like the halter style. I usually surf online for clothes. I got a decent halter tankini from VS it offers great support for the girls and they do make larger sizes. The board shorts are available everywhere in Hawai'i in all sizes. Some online stores have um too just do a google search. The upside of this style is that you don't have to worry about pulling your bikini out of your butt, it's supper comfortable and can be very stylish. The downside, a good tankini with bra support can cost $40 and up. Board shorts can cost a lot too, especially, if you go for name brands.