The caves were formed through thousands of years of erosion caused by the Ionian Sea waves hitting the soft limestone bedrock.
The water depth in the caves can reach over 20 meters, creating a distinct deep navy hue.
The vertical cliffs surrounding the caves reach heights of up to 300 meters above sea level.
The area is a designated nesting site for the endangered loggerhead sea turtle (Caretta caretta).
Keri Caves are a series of sea-level limestone arches and caverns located on the southwest coast of Zakynthos. The caves are accessible only by boat due to the vertical white cliffs that shield them from the island's inland roads. The crystalline, deep-blue water within the caves is caused by the light refraction against the submerged white limestone walls. Visitors often find small pebbled beaches tucked inside the larger cave openings during low tide. The site remains a natural formation without visitor infrastructure or artificial lighting. The geological structure is part of the protected marine area of the Ionian Sea, home to the endangered Caretta caretta sea turtle. Boat tours departing from Keri Lake frequently integrate the caves with visits to nearby Marathonisi island.
The entrance to the largest arch, where the contrast between the white cliff exterior and the blue cave interior is most visible.
Bring a waterproof camera or phone pouch to capture images inside the caves.
Use high-factor, reef-safe sunscreen if planning to swim in the cave waters.
Book a small boat tour rather than a large vessel to ensure access to the narrowest cave inlets.
Avoid visiting on windy days, as the boat access to the caves can be canceled due to high swells against the cliffs.
Accessible primarily during the summer season from May to October; completely dependent on sea conditions.
