Oceans, Seas and the Straits That Connect Them

The smallest, shallowest and coldest ocean, it is largely covered by drifting sea ice, and much of its water arrives from the Atlantic and Pacific through narrow connecting straits. That dependence on straits is why the path begins here.

This strait joins the Pacific, through the Bering Sea, to the Arctic Ocean, through the Chukchi Sea. It is about 82 kilometers across at its narrowest and no more than about 90 meters deep, and in glacial periods falling seas exposed the Beringia land bridge.

The Southern Ocean encircles Antarctica and is defined less by coastlines than by the Antarctic Circumpolar Current. It was formally recognized as the world fifth ocean in 2021, so its boundary is partly a convention.

A marginal sea of the Southern Ocean named for James Clark Ross, who charted it in 1841. In 2016 it became a marine protected area of about 1.55 million square kilometers, the largest in the world at the time.

The third largest ocean, and the only one named for a single country. Its seasonal reversal of winds and currents drives the South and Southeast Asian monsoon.

The only sea passage from the Persian Gulf to the open ocean, about 167 kilometers long and as narrow as 39 kilometers. In the mid-2020s about a quarter of the world seaborne oil trade passed through it each year.

Between the Malay Peninsula and Sumatra, this strait links the Indian Ocean to the Pacific. Its average depth of only about 25 meters limits ship size and defines the Malaccamax standard, and it is the world busiest shipping lane.

This strait connects the Atlantic to the Mediterranean and separates Europe from Africa, narrowing to about 14.2 kilometers. Ferries cross in as little as 35 minutes.

A natural strait running about 31 kilometers from the Black Sea to the Sea of Marmara, with Istanbul on both shores. At its narrowest, about 700 meters, it is the world narrowest strait used for international navigation.

A shallow shelf sea between Great Britain and mainland Europe, mostly under 90 meters deep, though the Norwegian Trench reaches roughly 700 meters. Fed by rivers such as the Rhine, Elbe and Thames, it has been a major shipping and fishing ground for centuries.

The path ends where sea meets land. The Wadden Sea along the Dutch, German and Danish coast is the largest unbroken system of intertidal sand and mud flats in the world, and UNESCO inscribed it as a World Heritage Site in 2009.