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.
What she said. Except I'm from Cali with family from Hawai'i. But definitely a big YES on the board shorts with tankini top. Bikinis are great for sunbathing and looking cute, but if you want something that you're sure will stay with you, go with board shorts and a tankini top. Lots more reliable.
My current outfit is a pair of black boardshorts with wide stripes up the sides in a dark turquoise mesh, with a matching racerback tankini top. Got it at JC Penneys, I think.