East of Cape Skinari, on the northern part of the island, are the Blue Caves. A series of geological formations have created the seascape. Natural arches have been carved out by erosion, but these caves are most famous for the color of the water in it’s deepest hollows, a deep azure color which is most striking in the morning when the light is at it’s brightest, hence the name Blue Caves. Kianoun cave is the biggest of the caves. In order to reach there you can hire a boat or go on a tour.
There are actually Blue Caves at 3 locatons around the island.
1, At Cape Skinari on the northern tip of the island – these are the most spectacular. There are several boats offering trips from Agios Nikolaos Port, also from Makris Gialos Alikes and Alykanas. You can hire a “self-drive” motorboat for the day from from several operators in Alykanas to visit the blue caves and then spend a leisurely afternoon exploring the north-east coast on your way back. These caves are also on the itinerary of the large round-the-island cruise ships operating out of Zakynthos Town.
2. Keri – also pretty good
3. Porto Vromi – Not as spectacular, you will visit these as part of the tours to the ship wreck.