The western coast of Paxos abounds in sea caves, some of them are so big that cruise boats and ships can easily go inside (like Ypapandi cave). They can be reached only by sea and in order to see them, you can take advantage of the organized daily boat trips or rent a boat and visit the caves yourselves.
The most popular cluster of sea caves on the island is near Erimitis beach and all boats and ships stop here for swimming and rest. The sea water around the caves is vivid blue and thus they call them "the blue caves". The roof of one of the caves has collapsed and formed a hole through which the sunshine peeks inside. The imposing rock of Ortholithos (a huge vertical rock which sticks out of the sea) is near the Blue caves.