Quick Answer
The Mediterranean Sea has an average depth of approximately 1,500 metres (4,920 ft) and a maximum depth of 5,267 metres (17,280 ft). The maximum depth is at the Calypso Deep in the Hellenic Trench, south of the Peloponnese in Greece. The basin is divided into the western and eastern Mediterranean by the Strait of Sicily, where depths drop to about 400 m. Both basins reach much deeper in their centres. By comparison, the average depth of all oceans is about 3,800 m, making the Mediterranean shallower than the open ocean but still substantially deeper than most regional seas.
At a glance: Mediterranean Sea depth
| Measurement | Depth |
|---|---|
| Maximum depth | 5,267 m (17,280 ft) at the Calypso Deep, Hellenic Trench, south of Peloponnese |
| Average depth | 1,500 m (4,920 ft) |
| Western basin maximum | ~3,800 m |
| Eastern basin maximum | ~5,267 m |
| Strait of Gibraltar (entry from Atlantic) | ~280 m |
| Strait of Sicily (between basins) | ~400 m |
| Surface area | 2,510,000 km² |
| Volume of water | ~3.75 million km³ |
The Calypso Deep: maximum depth
The deepest point in the Mediterranean Sea is the Calypso Deep, located in the Hellenic Trench off the southern coast of the Peloponnese, Greece. The depth — 5,267 metres — was first measured in detail in 1965 by the research vessel Calypso commanded by Jacques Cousteau, hence the name. Modern multibeam surveys have refined the figure but kept it close to 5,267 m.
The Calypso Deep is part of the larger Hellenic Trench system, where the African tectonic plate subducts under the Aegean Sea Plate. This ongoing subduction is also the cause of frequent earthquakes in Greece and Turkey, and the explosive volcanism of Santorini.
Why is the Mediterranean shallower than the open ocean?
The Mediterranean averages 1,500 m vs the global ocean average of 3,800 m. Three reasons:
- Continental shelves — about 30% of the Mediterranean is shallow continental shelf, less than 200 m deep. The Adriatic and the northern Aegean are particularly shallow.
- Two semi-enclosed basins — the Sea is restricted to the relatively narrow basin between Africa, Europe and the Levant. There are no abyssal plains the size of the Pacific or Atlantic.
- Closing of Tethys Ocean — the Mediterranean is the closing remnant of the ancient Tethys Ocean. Over 30+ million years, the African plate has been pushing Europe-ward, narrowing and shallowing the basin.
The two basins: western and eastern Mediterranean
The Mediterranean is divided by the Strait of Sicily into two distinct basins with different depths:
- Western Mediterranean: from Gibraltar to Sicily; max depth ~3,800 m at the Tyrrhenian Sea south of Sardinia. Includes the Ligurian Sea, Tyrrhenian Sea, Balearic Sea and Alboran Sea. Generally cooler and saltier than the eastern basin in summer.
- Eastern Mediterranean: from Sicily to the Levant; max depth 5,267 m at the Calypso Deep. Includes the Ionian, Adriatic, Aegean and Levantine seas. Warmer in summer; more variable salinity.
The Strait of Sicily acts as a hydraulic barrier between the basins. Surface water moves east-to-west; deeper water moves west-to-east in the opposite direction. This circulation pattern, called Mediterranean overturning circulation, is part of the global thermohaline circulation.
Surface area and volume
- Surface area: 2,510,000 km² — about half the size of India.
- Volume: 3.75 million km³ — about 0.7% of the Atlantic’s water volume.
- Coastline: 46,000 km, touching 22 countries on three continents.
- Length east-west: 3,860 km, Gibraltar to the Lebanese coast.
- Width north-south: maximum 1,030 km, between France and Algeria.
Compared to other seas
- North Sea: avg depth 95 m, max 700 m — much shallower than Mediterranean.
- Black Sea: avg depth 1,253 m, max 2,212 m — similar profile to the Mediterranean.
- Caribbean Sea: avg depth 2,200 m, max 7,686 m — deeper basin.
- Red Sea: avg depth 490 m, max 2,211 m — much shallower.
- Pacific Ocean: avg depth 4,280 m, max 10,924 m (Mariana Trench) — vastly deeper.
What lives at Mediterranean depth?
The deeper Mediterranean has a distinctive ecosystem:
- Surface (0-200 m): well-lit photic zone with most fish, dolphins, sharks and turtles.
- Mesopelagic (200-1,000 m): twilight zone with deep-sea anglerfish, lanternfish, large jellyfish.
- Bathypelagic (1,000-4,000 m): dark depths with bioluminescent species, deep-sea sharks.
- Abyssal (4,000+ m): only the Calypso Deep and similar trenches reach this depth; pressure 500+ atmospheres; only specialised species.
The Mediterranean has lost much of its biodiversity to overfishing, plastic pollution and climate change. Average sea temperatures have risen 1.5°C since 1990, with knock-on effects on fish migration and bleaching of marine plant communities.
Frequently Asked Questions
How deep is the Mediterranean Sea on average?
The Mediterranean Sea has an average depth of approximately 1,500 metres (4,920 ft). This is shallower than the global ocean average of 3,800 m, but deeper than most regional seas like the North Sea (95 m) or Red Sea (490 m).
What is the deepest part of the Mediterranean Sea?
The deepest point is the Calypso Deep at 5,267 metres (17,280 ft), located in the Hellenic Trench off the southern coast of the Peloponnese, Greece. It was named after the research vessel Calypso commanded by Jacques Cousteau, which first measured it in detail in 1965.
Is the Mediterranean deeper than the Atlantic?
No, the Mediterranean is much shallower than the Atlantic. The Mediterranean averages 1,500 m; the Atlantic averages about 3,646 m. The deepest point in the Mediterranean (5,267 m) is shallower than the average Atlantic depth.
What is the difference between the western and eastern Mediterranean depths?
The Mediterranean is divided by the Strait of Sicily. Western basin: max depth ~3,800 m (Tyrrhenian Sea). Eastern basin: max depth 5,267 m at the Calypso Deep south of the Peloponnese. The Strait of Sicily itself is only ~400 m deep, acting as a hydraulic barrier between the basins.
Why is the Mediterranean shallower than the open ocean?
Three reasons: (1) about 30% is shallow continental shelf less than 200 m deep, (2) the Sea is a relatively narrow semi-enclosed basin between Africa, Europe and the Levant with no abyssal plains the size of major oceans, and (3) the basin is the closing remnant of the ancient Tethys Ocean — narrowing and shallowing as the African plate pushes Europe-ward.
How big is the Mediterranean Sea?
Surface area: 2,510,000 km² (about half the size of India). Volume: 3.75 million km³. Coastline: 46,000 km, touching 22 countries on three continents (Europe, Africa, Asia). Maximum east-west length: 3,860 km from Gibraltar to Lebanon.
Recommended on Amazon
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- Atlas of the Mediterranean Sea — illustrated atlas with depth charts and basin geology
- Lonely Planet Mediterranean Europe — travel guide to Mediterranean coastal countries
- The Mediterranean and the Mediterranean World (Braudel) — classic deep history of the sea and its peoples