Bac Lava: Durdle Door at West Lulworth (between Poole and Weymouth) is a beautiful and much-photographed landmark beach of the south coast. From the car park at Lulworth there is a steep walk over cliffs and down a well-maintained (but uneven natural rock) staircase to the shingle beach.
Steep shelving entry to the sea. Take goggles and swim under the door. Look out for the shoals of sand eel and mackerel that shelter between the arch and the beach.
In early summer you might hear artillery fire at the nearby Tyneham ranges, a strange contrast to the families sunbathing on the beach.
The tide ebbs through the east end at quite a rate, so keep an eye on the shore to see if you're starting to drift.
Kate Rew: If nature is your church, Durdle Door is it's cathedral. Swimming under the huge arch inspires wonder: the rock doming arching above us, the buoyant sea holding us aloft. The best aspect is swimming out through the arch into the open sea - it feels like an adventure, a journey into boundless possibility.
Alex Evershead Willatt: Awesome swim but very busy in August. Be aware no fires or bbqs are allowed.
Be very careful on and outgoing tie. Also check the wind and sea state before entering the water. Never jump here there is a reef under the arch.