Mediterranean · Greece
Kea Channel
Titanic's sister ship, HMHS Britannic, rests largely intact at up to 122 m
Photo: Allan C. Green · Public domain
Two liners requisitioned for the First World War went down in this strait between Kea and Cape Sounion within two weeks of each other in November 1916, both mined by the German submarine U-73. HMHS Britannic, Titanic's sister ship and the largest intact passenger wreck on any seabed, lies undisturbed between 80 and 122 m. SS Burdigala, a former transatlantic liner, lies broken in two about two nautical miles away, deck around 53 to 60 m and seabed near 70 m. Neither is a walk-up charter: both sit under Greek antiquities jurisdiction, dived only as closed-circuit trimix expeditions.
About diving in Kea Channel
The Kea Channel, between the island of Kea and Cape Sounion on the Attic mainland, was an Allied shipping lane in the First World War and a German minefield at the same time. On 14 November 1916 the French troop carrier SS Burdigala struck a mine laid by U-73 and sank northwest of Kea; seven days later, on 21 November, the hospital ship HMHS Britannic hit the same minefield and went down 55 minutes later with the loss of 30 of the 1,066 people aboard. The two hulls now lie about two nautical miles apart, a First World War memorial that neither island nor divers can easily reach.
The two wrecks sort by depth and by what a team can actually do on them. Burdigala is upright and broken in two, her deck reported between about 53 and 60 m depending on the source and her seabed near 70 m — serious trimix diving but within reach of a strong technical team on a single tank of gas. Britannic is another order of problem: she lies on her starboard side largely intact, her shallowest point reported at 80 to 90 m by early expeditions and her deepest point close to 120 m, so every dive on her runs on closed-circuit rebreathers with staged decompression and a shot line placed section by section rather than a swim end to end.
Access to both wrecks runs through Greece rather than through any dive shop. Since 2003 Greece's Ephorate of Underwater Antiquities has held jurisdiction over any wreck more than fifty years old, so both sites need its permission, and Britannic additionally needs the agreement of British historian Simon Mills, who bought the wreck in 1996 and runs the Britannic Foundation. Both are dived look-only: a technical diver died on Britannic in 2019, and the one sanctioned removal from her — a 2025 recovery of the ship's bell and other artefacts for a new Piraeus museum — was carried out by an 11-diver team under that same permit.
Not all diving here needs a rebreather. Kea itself, about an hour by ferry from Lavrio, is a scuba destination in its own right, with wall, cavern and wreck diving, and its recreational highlight is the paddle steamer Patris, which struck a reef off the southwest coast in February 1868 and lies in two sections from about 26 to 52 m. On the mainland side, boats from Lavrio work the shores of Makronisos: a rock canyon from 5 to 27 m that opens onto a wall, a small Piper aircraft on the seabed at 16 to 22 m, and the broken cargo ship Apollonia on a reef that runs from 2 to 35 m. These are the dives for anyone who comes to the channel without a trimix card.
Best time to dive Kea Channel
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Season | Off-season | Off-season | Off-season | Fair | Good | Prime | Good | Good | Prime | Good | Fair | Off-season |
| Sea surface | 16°C61°F | 15°C59°F | 15°C59°F | 16°C61°F | 18°C64°F | 22°C72°F | 25°C77°F | 26°C79°F | 25°C77°F | 23°C73°F | 20°C68°F | 17°C63°F |
| Daytime high | 17°C63°F | 17°C63°F | 18°C64°F | 21°C70°F | 25°C77°F | 29°C84°F | 31°C88°F | 30°C86°F | 29°C84°F | 25°C77°F | 22°C72°F | 19°C66°F |
| Rain | 79 mm3.1 in | 72 mm2.8 in | 51 mm2.0 in | 23 mm0.9 in | 17 mm0.7 in | 12 mm0.5 in | 4 mm0.2 in | 7 mm0.3 in | 24 mm0.9 in | 51 mm2.0 in | 62 mm2.4 in | 86 mm3.4 in |
| Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|
| Off-season | Off-season | Off-season | Fair | Good | Prime |
| Sea surface | |||||
| 16°C61°F | 15°C59°F | 15°C59°F | 16°C61°F | 18°C64°F | 22°C72°F |
| Daytime high | |||||
| 17°C63°F | 17°C63°F | 18°C64°F | 21°C70°F | 25°C77°F | 29°C84°F |
| Rain | |||||
| 79 mm3.1 in | 72 mm2.8 in | 51 mm2.0 in | 23 mm0.9 in | 17 mm0.7 in | 12 mm0.5 in |
| Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|
| Good | Good | Prime | Good | Fair | Off-season |
| Sea surface | |||||
| 25°C77°F | 26°C79°F | 25°C77°F | 23°C73°F | 20°C68°F | 17°C63°F |
| Daytime high | |||||
| 31°C88°F | 30°C86°F | 29°C84°F | 25°C77°F | 22°C72°F | 19°C66°F |
| Rain | |||||
| 4 mm0.2 in | 7 mm0.3 in | 24 mm0.9 in | 51 mm2.0 in | 62 mm2.4 in | 86 mm3.4 in |
2011–2025 averages. Sea surface: NOAA Coral Reef Watch, measured at the surface, so deeper water can run colder. Daytime high and rain: NASA POWER.
May to June: the best start to the season. The etesian north wind, the meltemi, begins around mid-May but has not yet settled in, and the water is warming towards its summer range of about 20 to 26 °C. July and August: workable but less dependable, because the meltemi can reach force 7 to 8, is strongest in the afternoon and sometimes blows for days without a break, which stops ferries and small boats alike; morning dives and flexible schedules are the rule. September: prime again as the wind fades around mid-month. October: good, with shorter days. April and November are marginal, and from December to March the channel sees no planned technical diving.
Kea Channel water temperature and weather by month
The sea surface runs from 15 °C (59 °F) in February to 26 °C (79 °F) in August. It is 24 °C (75 °F) or warmer from July to September. Most rain falls from October to March, peaking at about 90 mm (3.5 in) in December; it stays largely dry from April to September. Daytime highs reach 31 °C (88 °F) in July and drop to 17 °C (63 °F) in February. The coldest water here is about 15 °C (59 °F), so pack a 7 mm suit with a hood, or a semi-dry.
Dive types & marine life
The deep wrecks are dived for their history rather than their fish. Life belongs to the shallower sites on the Makronisos side: groupers are common on the canyon walls and around the Apollonia wreck, breams school over the rock, sardines and baitfish gather in big shoals, and nudibranchs, crinoids and octopus live on the wreckage. Mediterranean monk seals are reported now and then.
- Wreck
- Groupers
- Sardine baitballs
- Nudibranchs
- Octopus & cuttlefish
Best dive sites in Kea Channel
- 1
HMHS Britannic
Titanic's sister and the largest ship lost in the First World War, on her side at 80 to 122 m.
- 2
SS Burdigala
Former German liner mined a week before Britannic; upright in two halves, deck at 53 to 60 m.
- 3
Patris Wreck
Paddle steamer lost off Kea in 1868, cut in two with a paddle wheel; the recreational highlight.
- 4
Macronisos Canyon
Rock canyon off Makronisos from 5 to 27 m, ending on a wall to 45 m with groupers and sponges.
- 5
Pipper
Small Piper aircraft lying intact at 16 to 22 m off northern Makronisos, in reliably good visibility.
- 6
Apollonia Wreck
Broken cargo ship on a Makronisos reef from 2 to 35 m, dived only when the sea is calm.
Site guides
Wreck
A scattered cargo wreck on a reef running from 2 m to 35 m
Wreck
Largest intact passenger shipwreck on any seabed, found by Jacques Cousteau in 1975
The canyon exit opens onto a wall that falls to 45 m
Wreck
An 1868 paddle steamer, broken in two with a paddle wheel still in place
Wreck
An intact light aircraft on the bottom between 16 and 22 m
Wreck
Sunk by the same minefield as HMHS Britannic, seven days before her
How to get to Kea Channel
Kea is reached by a roughly hour-long ferry from Lavrio, itself about an hour southeast of Athens by road; the port of Korissia is where charter boats leave from. There is no walk-up dive-shop trade at these depths — trips are private technical charters arranged well ahead, built around a settled weather window.
Photos from Kea Channel
Unknown author · Public domain
NASA · Public domain
Unknown author · Public domain
Questions divers ask
Where is the Kea Channel?+
It is the strait between the island of Kea and Makronisos, just off Cape Sounion at the southern tip of Attica. Kea lies about 20 km from Sounion and 60 km southeast of Athens, and ferries cross to it from Lavrio in about an hour.
Can you dive the Britannic wreck?+
Only on a permitted technical expedition. Greece's Ephorate of Underwater Antiquities must approve any dive on a wreck over fifty years old, the wreck's owner must agree, and at 80 to 122 m every dive runs on closed-circuit trimix with long decompression.
How deep is the Britannic wreck?+
She lies on her starboard side in about 122 m of water, with her shallowest parts reported at 80 to 90 m. The Burdigala, two nautical miles away, is shallower: her deck is at about 53 to 60 m and the seabed near 70 m.
Is there diving in the Kea Channel for recreational divers?+
Yes. The paddle steamer Patris off Kea, reported at about 28 m with a deeper section to 52 m, is the island's recreational highlight, and boats from Lavrio dive the Makronisos side: a canyon from 5 to 27 m, a Piper aircraft at 16 to 22 m and the Apollonia wreck.
When is the best time to dive the Kea Channel?+
June and September. Expeditions run from about May to October, but the meltemi north wind blows from mid-May to mid-September, can reach force 7 to 8 and is strongest in the afternoons, so the edges of that window are the most reliable.
Sources
- Kea Channel — Wikipedia
- Kea (island) — Wikipedia
- HMHS Britannic — Wikipedia
- HMHS Britannic Expedition Summary 1976–1999 — Simon Mills, via Wayback Machine
- Artefacts recovered from Titanic's sunk sister ship — BBC News
- SS Burdigala — Wikipedia
- Ephorate of Underwater Antiquities — Wikipedia
- Etesian — Wikipedia
- Patris Wreck (Πατρίς) — Scubago
- Macronisos Canyon — Scubago
- Pipper — Scubago
- Apollonia wreck — Scubago
Photo credits
- Black-and-white photograph of the four-funnelled liner HMHS Britannic underway at sea, marked with a dark band and red crosses as a hospital ship. by Allan C. Green, Public domain, via Wikimedia Commons
- Sepia postcard photograph of the three-funnelled liner SS Burdigala steaming through calm water, her name visible on the bow. by Unknown author, Public domain, via Wikimedia Commons
- NASA astronaut photograph from orbit of the island of Kea, the narrow island of Makronisos, and Cape Sounion, with open blue water between them. by NASA, Public domain, via Wikimedia Commons
- Weathered black-and-white photograph of HMHS Britannic at anchor, her four funnels and hull with hospital-ship red cross markings reflected in calm water. by Unknown author, Public domain, via Wikimedia Commons
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