Snacks for energy and drinks for hydration under the sun.

Trashbag, maybe not for what you bring but for the bits of crap you’ll find scattered around the beach

Spare change for ice cream

UV proof t-shirt for midday swimming

Like a swimsuit but covers shoulders and arms. If you get sunburned easily, this can save your skin. Sunscreen works, but it’s not perfect in the water. Most people don’t use one, but then most people have unhealthy bright red sunburns

I’m not going without a book/ereader.

And multiple cameras.

(Edit) particularly for the reader, I should mention “be careful of sand” and maybe have one of those little duster cans around to make sure the ports are clear. But it’s too much of what I value in between soaking in the water to not bring.)

• e-ink reader
• flip flops
• cooler

A good book.