Best things to do in Cornwall with kids.

A ruined castle on a headland that looks like it was drawn by a child who was told to draw the most dramatic castle they could imagine. Tintagel trades on the Arthurian legend — the claim that this is the birthplace of King Arthur — and while the history is more complicated than that, the setting is beyond argument. The new footbridge connecting the mainland to the island headland is a piece of engineering that's worth the visit on its own: a pair of cantilevered steel arms that don't quite meet in the middle, leaving a deliberate gap you can see through to the sea below. Children who can manage the steps — and there are many, steep ones — will spend an hour exploring the ruins and another hour refusing to leave the beach in the cove below. Merlin's Cave at low tide is the finale.

A narrow-gauge steam railway in a wooded valley between Newquay and Truro, and the single best morning out in Cornwall for children under six. The train itself is small — a proper miniature steam engine pulling open carriages through a mile of woodland — and the journey takes about fifteen minutes. At the far end there are boating lakes, a maze built from Cornish hedging, and a miniature golf course that's more charming than it has any right to be. The whole thing is low-key in a way that feels deliberate: no blaring music, no mascots, no hard sell at the gift shop. Children ride the train, feed the ducks, get a bit muddy, and leave happy. It runs from Easter to October; check the timetable before you go, because services are limited outside school holidays.

No admission fee, no booking, no gift shop. Rock pooling at Chapel Porth — a National Trust beach between St Agnes and Porthtowan — is the purest family activity in Cornwall: a low tide, a bucket, and an hour of crouching over shallow pools looking for crabs, blennies, anemones, and the occasional starfish. The rock shelves at Chapel Porth are wide, flat, and particularly good for younger children because the pools are shallow and the access is easy. The key is timing: you need a low spring tide, which means checking the table the night before and arriving two hours before low water. The National Trust car park at the top charges members nothing; bring towels and a change of clothes, because someone will end up in a pool.

A full-sized heritage steam railway running six and a half miles from Bodmin General to Boscarne Junction, through the kind of quiet, green Cornish countryside that the coast path never shows you. This is a proper railway — Great Western tank engines pulling mark-one coaches along a branch line that closed in the 1960s and was rebuilt by volunteers. Children who have outgrown the miniature scale of Lappa Valley will find this more convincing: the engine is loud, the carriages are real, and the whistle at level crossings is the kind of noise that ends up in stories told for years. The Camel Trail crosses the line at Boscarne Junction, which makes for a good combination day — train one way, cycle or walk back. Services run weekends year-round and daily in summer.