Which Body of Water Borders Turkey, Greece, Switzerland, and Sudan? None.

No single body of water borders all four countries. Each borders different seas; Switzerland borders none.

Country-by-Country Coastlines

• Turkey: Black Sea (north), Aegean Sea (west), Mediterranean Sea (south).
• Greece: Aegean Sea (east), Ionian Sea (west), Mediterranean Sea (south).
• Switzerland: Landlocked. Borders no sea or ocean. Major lakes: Geneva, Constance, Zurich, Maggiore (shared).
• Sudan: Red Sea (northeast coast, ~850 km).

Shared Waters?

• Aegean Sea: Borders Turkey and Greece (but not Switzerland or Sudan).
• Mediterranean Sea: Borders Turkey and Greece (via Aegean/Levantine basins); Sudan accesses via Suez Canal/Red Sea, but does not directly border the Mediterranean.

The only water body bordering three of them is the Mediterranean (Turkey, Greece, and indirectly Sudan via Red Sea connection), but Switzerland's landlocked status makes a common border impossible.