Marathonisi Turtle Island

Zakynthos Town · Ionian Islands · Greece

Marathonisi, known locally as Turtle Island, is a small uninhabited islet shaped roughly like a turtle shell that sits in Laganas Bay off the southern coast of Zakynthos. The island lies within the National Marine Park of Zakynthos, established in 1999 to protect the most important loggerhead sea turtle nesting habitat in the Mediterranean. For divers, Marathonisi offers reliable turtle encounters and healthy Mediterranean reef in warm, clear Ionian water. The boat ride from Keri or Laganas takes fifteen to twenty minutes, skirting the dramatic cliffs of the southern coast before rounding into the sheltered bay. Marathonisi appears as a low, green island with a white sand beach on its southern side, where Caretta caretta turtles haul ashore on summer nights to lay their eggs. The rocky reef around Marathonisi drops gradually from the waterline to around twenty-five metres, with large boulders creating swim-throughs and overhangs that shelter Mediterranean reef life. Dusky groupers, increasingly rare elsewhere in the Greek islands due to overfishing, maintain a visible population here under the park's protection. Octopuses occupy crevices in the rocks, their intelligent eyes tracking divers. Moray eels extend from holes in the reef face. The turtle encounters are what draw most divers. Loggerheads rest on rocky ledges, tucked into overhangs where they sleep for hours. Others graze on Posidonia seagrass meadows, methodically working through the beds in a manner reminiscent of underwater cattle. These are large animals, often seventy centimetres or more in shell length, and their calm acceptance of diver presence allows for sustained observation that is genuinely moving. The National Marine Park regulations ensure encounters remain ethical. Licensed dive operators brief participants on approach distances and behaviour, and the limited number of permits prevents overcrowding. There is no touching, no chasing, no blocking of swimming paths. The result is an encounter on the turtle's terms. Above water, Marathonisi's beach and sea caves add to the day's exploration. The island is uninhabited and undeveloped, accessible only by boat, and the combination of turtle diving, Mediterranean reef, and a pristine island makes a day here among the most rewarding in the Ionian.