Marathonisi islet is locally nicknamed 'Turtle Island' due to its shape resembling a swimming turtle.
The island serves as one of the most critical nesting sites in the Mediterranean for the endangered Caretta-caretta loggerhead sea turtle.
The caves are formed by the chemical weathering of the island's soft limestone bedrock by Mediterranean saltwater.
Strict protection laws in Laganas Bay prohibit boat anchoring in specific zones to prevent damage to turtle nests and seagrass meadows.
Marathonisi is part of the National Marine Park of Zakynthos, the first of its kind established in Greece for marine conservation.
Marathonisi Caves are a series of sea-eroded grottoes located along the coastline of Marathonisi, an uninhabited islet in Zakynthos, Greece. These limestone caves are accessible primarily by small private boats or guided sea excursions departing from Laganas Bay. The site is situated within the protected zone of the Zakynthos Marine Park, established to safeguard the nesting grounds of Caretta-caretta loggerhead sea turtles. The water inside and around the caves is known for its high clarity and deep turquoise coloration caused by sunlight refraction. Visitors frequently swim or snorkel directly from boats into the cavern mouths. The rock formations are characterized by vertical cliffs and narrow channels that allow light to illuminate the underwater sandy floor. Wildlife viewing opportunities include sea turtles, which are often spotted in the vicinity during the summer breeding season.
From the water looking outward from within the largest cave arch, framing the turquoise sea against the rock walls.
Bring a waterproof camera or phone case to capture underwater imagery near the cave openings.
Utilize a snorkel mask to observe the marine life around the cave entrances, where depth visibility is highest.
Book small boat tours rather than large group catamarans to access the narrowest cave inlets.
Do not attempt to land on the protected sandy nesting beaches of the islet, as these are cordoned off during turtle nesting season.
Boat access is restricted during the winter months due to rough seas; some areas may be inaccessible during peak turtle nesting activity.
Maintain a quiet volume near the shore, do not touch or disturb sea turtles, and adhere strictly to all no-anchor zones.
