Unless you’re going to the beach with a larger group, you are going to run into a problem: you are in the water, while your stuff is not; how do you enjoy your swim without being worried it will get stolen?
Tip #1. Don’t take anything unessential with you. Yes, the camera can stay home. No, thieves don’t steal beach towels.
Tip #2. If you have money, hide it well. A wallet is obvious and easy to find; look for alternatives. My low-tech solutions is taking very little money and throwing it inside the beach bag. But (if I didn’t hate flip flops) I would get the Stash Reef Sandals.
The idea is brilliant: they have a little “drawer” inside the sole where money, credit cards or keys can be stashed. I’ve never ever heard of shoes being stolen from the beach, so your valuables would be much safer than anywhere else. High quality footwear that’s more than just a pair of flip-flops? Win.