This cave is so well hidden you almost don't know it is there until you are in it. The entrance is just wide enough to get a boat in and once inside the chamber has a high roof. There are several ledges which are good fun for diving from and the water is plenty deep enough.
By sea only. The nearest port is Fornells and you could go by boat, kayak, paddleboard or similar. There are vertical cliffs all along this section of coast and the entrance to the cave is very difficult to identify. Take the GPS co-ordinates if you want to be sure of going straight to the right spot. To actually enter in to the cave the sea needs to be almost completely flat but a boat of up to around 5 metres can turn around inside.
The sea needs to be really flat so you need a very light (ideally offshore) wind. If you go by boat be ready to fend off from the edges. There are several other caves between Fornells and Englishman's cave, though none that you could park a boat in.