Greece – Ionian Islands

The Ionian islands run down Greece's western coast, and their limestone shores hide an unusual number of sea caves. On Zakynthos the Keri and Marathia coast has swim-through caves with milky sulphur water, an underwater arch and a turtle-nesting islet, Marathonisi, inside the National Marine Park. Paxos has big caverns on its west coast and a long cave inside the islet of Mongonisi. Corfu's north-west and north-east shores offer walls, caves and two wrecks near Nissaki. Lefkada has the drift and wall dives off Cape Ducato, and around Fiskardo in northern Kefalonia a local centre dives caves such as The Temple, a cliff drop-off and a 50 m barge wreck. Greek law now allows diving practically everywhere with a licensed centre, but wrecks over 50 years old, protected areas and archaeological zones are tightly controlled.

Facts

Best season: Roughly May to October. Fiskardo Divers quotes water from about 19 °C in April to 28 °C in August; the Zakynthos centre Diver's Paradise advises a 7 mm suit generally, 5 mm in May and October and 3–5 mm in July and August. The centres' own pages do not publish opening dates, so confirm them
Water and visibility: Fiskardo Divers reports visibility up to 40 m and calm, often current-free water; Paxos Oasi Sub gives 18 °C to 27 °C in summer and visibility sometimes over 30 m. Freshwater inside some caves (Paxos, Corfu) can cut visibility to a few metres
Getting there: Airports: Zakynthos (ZTH), Corfu (CFU), Kefalonia (EFL) and Preveza–Aktion (PVK) for Lefkada. Paxos and Ithaca are reached by ferry or excursion boat
Diving rules in Greece: Under Law 3409/2005 as amended by Law 4688/2020 (as summarised by divelog.gr) only divers certified by a recognised provider may dive, always with a buddy. Diving is banned near shipping lanes and anchorages, in military areas, near cables and in protected marine areas where the law says so; spearfishing and collecting are forbidden; shipwrecks submerged more than 50 years may only be dived with a recognised provider; night diving needs a certified provider. A 2020 news report says depth limits were effectively removed. This is a secondary summary, not the law text – check current rules
National Marine Park of Zakynthos: The park in Laganas Bay has three marine zones; zone A bans boats, zones B and C limit speed and B bans anchoring (per zanteisland.com). Marathonisi and Pelouzo lie in the park and are dived by local centres, but we could not find the park's own diving rules online (the park website is down), so the exact regime is unverified. Eurodivers sells park dives with 'National Park Fees' included. Ask your centre and the managing body (NECCA)
Wrecks and antiquities: Since 2003 the Ephorate of Underwater Antiquities (Ministry of Culture) has jurisdiction over all wrecks of ships and aircraft more than 50 years old, and its permission is needed for surveys and photography dives on them. Never lift or move anything: amphora fragments are scattered at Pelouzo, Lefkada and Fiskardo. The Skala (Kefalonia) site is described by Kefalonia Diving Center as a declared underwater archaeological area
Hazards: Several caves are real overhead environments: the Submarine Cave on Mongonisi (Paxos) runs more than 250 m into the island, Fiskardo's Catacombs need technical cave training, and Zakynthos's Keri cave 1 is for advanced divers. Cape Ducato (Lefkada) has strong currents. Sulphur in some Zakynthos caves tarnishes silver jewellery

Season

Best months: Jun, Jul, Aug, Sep
Acceptable: Apr, May, Oct
Poor: Nov, Dec, Jan, Feb, Mar
Water temperature: 18–28 °C

Fiskardo Divers quotes about 19 C in April and 28 C in August; Paxos Oasi Sub gives 18–27 C in summer. Visibility is often over 30 m. The centres' own pages do not publish opening dates; most are likely closed in winter, so confirm.

Dive sites (38)

Paxos & Antipaxos

Alexander's Cave – 8–30 m, intermediate
Arch of the Temple – 5–20 m, intermediate
Blue Pot – 1–30 m, intermediate
Space Cave – 16–54 m, advanced
Submarine Cave (Mongonisi) – 0–15 m, advanced
Vassilis Cavern – 8–25 m, intermediate

Zakynthos

Arc de Triumph (The Arch) – 6–46 m, advanced
Butterfly Cave – 10–20 m, intermediate
Elephant Reef – 15–75 m, intermediate
Keri Caves – 9–30 m, intermediate
Marathia Caves – 0–12 m, intermediate
Marathonisi (Turtle Island) – 0–18 m, beginner
Octopus Reef – 2–40 m, beginner
Pelouzo Island reef – 3–18 m, intermediate
Two Columns – 5–40 m, advanced
White Reef – 0–40 m, intermediate

Corfu

Blue Eye (Swiss Cheese) – 3–30 m, advanced
Captain John's Wreck (Nissaki) – 10–35 m, advanced
City of Piraeus ferry wreck (Nissaki) – 37–43 m, advanced
Ducates Cave and deep wall – 3–60 m, advanced
Kapareli reef and caves – 0–35 m, beginner
Kolovri Island (Odysseus Rock) – 0–80 m, advanced
Monastery (Paleokastritsa) – 0–42 m, intermediate
Nissaki – The Wall – 12–27 m, intermediate
Skeloudi Island (Bobby Rock) – 3–60 m, intermediate
Sunday Cave – 1–6 m, advanced

Lefkada

Canyon (Vassiliki) – 8–34 m, advanced
Light House (Cape Ducato) – 5–50 m, advanced

Kefalonia & Ithaca

Christina ferry wreck (Myrtos, Kefalonia) – 0–25 m, intermediate
Emblissi (Fiskardo) – 0–10 m, beginner
Polis Bay (Ithaca) – 0–18 m, beginner
Skala (Kapros) archaeological site – 0–20 m, intermediate
The Barge (Fiskardo) – 5–22 m, intermediate
The Catacombs (Fiskardo) – 5–21 m, advanced
The Cliff (Fiskardo) – 12–40 m, intermediate
The Cyclops (Ithaca) – 17–40 m, advanced
The Secret of Venus (Fiskardo) – 3–30 m, advanced
The Temple (Fiskardo) – 5–26 m, advanced

Operators (9)

Diver's Paradise Dive Center – dive centre, Laganas Beach (Eleon Grand Resort & Spa, Tragaki, second base) – Zakynthos
Eurodivers Zante – dive centre, Monument Vezal, Laganas Beach, Zakynthos
Nero-Sport Diving Center – dive centre, Limni Keriou, Zakynthos
Apollo Corfu Diving Center – dive centre, Nissaki port, north-east Corfu
Paxos Oasi Sub – dive centre, Lakka, Paxos
Lefkas Diving Center – dive centre, Nikiana, Lefkada
Nautilus Diving Club – dive centre, Vassiliki beach (also Nidri and Sivota), Lefkada
Fiskardo Divers – dive centre, Fiskardo harbour, north Kefalonia
Kefalonia Diving Center – dive centre, Fiskardo and Argostoli, Kefalonia

Routes (4)

Site positions are approximate unless marked otherwise and are for orientation only – never for navigation. Most Ionian centres publish no coordinates; several positions come from community dive-site listings and were moved onto the water. Always dive with a licensed local centre, respect the National Marine Park of Zakynthos and archaeological finds, and check current rules.