Zakynthos (Zante) in Greece's Ionian Islands pairs easy limestone cave, arch and wall diving off the Keri peninsula with the National Marine Park of Zakynthos in Laganas Bay — Greece's first national marine park (1999) and the Mediterranean's most important loggerhead turtle rookery, averaging about 1,200 nests a year.
Destination info
Conditions, highlights, and the resident marine life.
Conditions
Water and air temperature across the year.
WaterAirDryShoulderWet
Description
Diving on Zakynthos centres on the southern Keri peninsula, where dive centres based in the small harbour of Limni Keriou run short boat trips (15–40 minutes) to roughly 20–30 sites strung along the limestone coast between Marathonisi islet and Cape Keri: torch-lit caverns the size of cathedrals, swim-through tunnels, arches, boulder slopes and walls dropping past 30 m in typically very clear water. The bays sit on the edge of the National Marine Park of Zakynthos, established by presidential decree in December 1999 as Greece's first national marine park to protect Laganas Bay's six loggerhead nesting beaches — about 1,200 Caretta caretta nests a year, monitored by ARCHELON since 1984 — and in-water turtle encounters around Marathonisi are a realistic prospect in summer, governed by strict approach rules (15 m distance, 6-knot boat speed limit). Mediterranean monk seals shelter in the peninsula's sea caves and are occasionally, but never reliably, met by divers. Expect Mediterranean rather than tropical marine life: groupers, morays, octopus and lobsters instead of clouds of reef fish, with the spectacle coming from rock architecture and light. The famous Navagio shipwreck lies on a beach in the island's northwest — a boat-trip photo stop, not a dive site, and the beach itself is currently closed to landings after landslides. Winter water drops to about 15–16°C, most centres operate roughly May to October, and high summer brings heavy tourist-boat traffic to Laganas Bay.
Highlights
What makes this dive worth the trip.
The National Marine Park of Zakynthos — Greece's first national marine park, founded in December 1999 — covers about 135 km² of Laganas Bay and its surroundings as a Natura 2000 site, protecting six discrete loggerhead nesting beaches totalling roughly 5 km; fishing is strictly prohibited throughout its marine zones, and a resident population of the Mediterranean monk seal is documented on the island's west coast.
Laganas Bay's six nesting beaches (5.5 km in total, including Marathonisi islet) host an average of about 1,200 loggerhead nests per year, recorded systematically by ARCHELON since 1984 — one of the longest-running sea-turtle monitoring projects in the world. The 550 m beach of Sekania has the highest nesting density and is an Area of Absolute Protection closed to the public.
Diving and swimming are permitted inside the marine park, but encounters are regulated: keep at least 15 m from turtles, observe a submerged turtle for no more than 15 minutes (10 minutes at the surface), and never touch or feed. Boats are capped at 6 knots, mooring is allowed only in Zone C, motorised water sports are banned year-round, and all fishing — including spearfishing — is prohibited.
Marine life
17 species you’re likely to encounter on a dive here.
Dive sites
7 signature sites at this destination.
Barakuda
A pinnacle rock formation riddled with holes, canyons and cracks, dived as a circuit from about 10 m down to 30+ m depending on conditions. Locally nicknamed the 'moray eel reef' for the density of Mediterranean morays in its crevices; schools of barracuda patrol the rock in the warm season, with groupers and violet aeolid nudibranchs on the walls. About 20 minutes from Limni Keriou; the deeper circuit suits divers comfortable below 25 m.
10–32 mintermediateDay boatLightVisibility 15–30 m
Marathia
A reef-and-wall site off the Marathia cape at the southern tip of the Keri peninsula, 15 minutes from harbour. Divers descend a rocky slope to a wave-sculpted wall with deep pockets and a steep drop-off — prime hunting ground for octopus spotting, with spiny and slipper lobsters wedged in the cracks, groupers, scorpionfish and elegant doris nudibranchs. Local operators report Mediterranean monk seals along this stretch of coast. Suits all training levels.
5–30 mbeginnerDay boatLightVisibility 15–30 m
Poseidon Cave
A two-chamber cavern system toward Cape Keri: the boat anchors over about 18 m, the lower chamber entrance lies at 22 m, and two vertical chimneys (wide enough for two to three divers) connect the chambers. Porous rock between them leaks a shimmering veil of millions of tiny air bubbles — the site's signature moment. Shrimps, crabs, lobsters and tube anemones live in the dark interior. Torches mandatory; depth plus overhead environment make this one for experienced divers.
15–26 madvancedDay boatNo currentVisibility 15–30 m
Faros
The farthest regular site (about 40 minutes by boat), beneath the Keri lighthouse near Cape Keri and the photogenic Mizithres rocks. Two roughly 30 m tunnels cut through the headland — the first wide enough for two divers side by side, the second with single-file sections — plus a huge cavern; swell compressing air in the tunnels produces booming 'cannon-fire' sounds. Maximum depth is only about 12 m, so despite the overhead sections it is run for all experience levels with torches. Monk seals are reported in the area.
3–12 mbeginnerDay boatLightVisibility 15–30 m
Oktopus
A rocky slope and wall 20 minutes from Limni Keriou where giant limestone boulders form dramatic weaving passages — about 10 m under the boat, dropping to roughly 30 m. A small cave with a large entrance and a narrow exit crack sits at mid-depth. The name is earned: octopus hide in the holes alongside spiny and slipper lobsters, moray eels and groupers. Works for beginners on the shallow line and experienced divers along the deeper wall.
10–30 mbeginnerDay boatLightVisibility 15–30 m
Keri Caves (Blue Cave)
The flagship site of the Keri peninsula, about 25 minutes by boat from Limni Keriou: a deep blue cavern roughly 75 m long and 'big like a cathedral', completely dark beyond the entrance glow, plus a second cavern whose surface layer is a milky sulphur 'soup' below a roof of roosting bats. Outside the caverns, reef walls and tunnels drop to about 30 m. Torches are mandatory; guides often have divers switch lights off on exit to enjoy the blue entrance glow. Mediterranean monk seals are occasionally found feeding or sleeping inside — keep your distance and do not pursue.
5–30 mintermediateDay boatNo currentVisibility 15–30 m
Marathonisi (Turtle Island)
A shallow circular dive (anti-clockwise) around the seaward back side of Marathonisi, the turtle-shaped islet in Laganas Bay whose beach is itself a protected loggerhead nesting site inside the marine park. Bizarre rock formations hold nudibranchs, triton shells and octopus, with schools of jacks in the blue; loggerhead turtles are regularly encountered in the surrounding shallows in summer and monk seal sightings have been documented. Only 15 minutes from Limni Keriou and suitable for every level — park rules apply: 15 m distance from turtles, no touching, 6-knot boat speed.
4–18 mbeginnerDay boatNo currentVisibility 10–25 m
Where to dive & stay
Local dive centers, resorts, and hotels.
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