Round Hole

A sea cave that's only accessible at low tide - that's the deal with Round Hole near Treyarnon. You're looking at a proper underground chamber carved into the cliffs, the kind of place where the Atlantic has done all the heavy lifting over thousands of years. The entrance is tight enough to feel like an adventure, and once you're through, there's a decent-sized cavern waiting with the sound of water echoing off the rock face.

It's genuinely worth the detour if you're staying anywhere near Padstow or Dennis Cove Campsite, but you absolutely have to check the tide tables first. Get it wrong and you'll be staring at water where the cave entrance should be. The walk down from the clifftop takes ten minutes or so, and you'll need decent shoes - the path's a bit loose and the rocks are slippery.

This works best for walkers and teenagers who fancy something a bit different from the standard beach day. Younger kids might find the entrance intimidating, and it's not the sort of place to linger for hours. Allow an hour total from the clifftop car park if you're not hanging about photographing the water patterns on the rock.

Sun Haven Holiday Park and Porthilly Beach are both within easy striking distance if you're basing yourself in the area. Combine it with the coastal path walks nearby - there's plenty of proper coastline to cover. Just don't attempt it on a rising tide.