If I'm swimming I just leave it at the truck. I figure everybody else there is just as naked as I am but if tempers flare or somebody or something looks out of place I grab the family and go.
Now if I'm just walking on the beach (with a shirt) I just wear my regular Raven Phantom with the XD45 service and an X300. If its daytime and I'm shirtless I toss my Springfield XDS 45 in a pocket with a spare mag in an opposite pocket since it only packs 6 rounds..