I had a look at map of the world and decided to note down some of the straits (narrow stretches of water between two larger bodies of water) or relatively narrow stretches of ocean. The following list mainly has those between different countries. There are countless more in archipelagos such as in Scandinavia, northern Canada, the Philippines, Indonesia and the Caribbean. Most distances shown refer to the narrowest width of water. The information is taken from the relevant Wikipedia entries (hence not to be taken as definitive) as well as the references given at the bottom.
- Cook Strait between the two main islands of New Zealand is 23km wide.
- Bass Strait between mainland Australia and Tasmania is around 240km wide and only 50 metres deep. The Tasmanian Aborigines were isolated from mainland Australia for around 8000 years after sea levels rose.
- Torres Strait between Australia and Papua New Guinea is 150km wide with at least 274 islands.
South East and South Asia
- The Malacca Strait between peninsular Malaysia and Sumatra is 805km long and as narrow as 2.8km at Phillips Channel (south of Singapore). It apparently carries one quarter of world’s trade goods.
- Sunda Strait between Java and Sumatra is 30km wide.
- Palk Strait between India and Sri Lanka is 30km wide at Adam’s Bridge (containing a chain of islands).
- Bab-el-Mandeb between Yemen in the Arabian Peninsula and the Horn of Africa is about 30km wide.
- Hormuz Strait between Oman and Iran across the Persian Gulf, is 54km wide at its narrowest point.
East and North Eurasia
- The Hainan (Qiongzhou) Strait between the island of Hainan and mainland China is 30km wide.
- The Taiwan Strait is 131km wide between Taiwan and China.
- Korea Strait between South Korea and southern Japan is about 200km wide.
- The largest island of Japan, Honshu, is 19.5km from the northern island Hokkaido (via the Tsugaru Strait), 15km from Shikoku (via the Inland Sea) and just 600 metres from the southern island Kyushu (via the Kanmon Strait).
- La Pérouse Strait between Sakhalin Island of Russia and Hokkaido Island of Japan is 40km wide.
- Tartar Strait between east mainland Russia and the island of Sakahlin is 7.3km wide.
- Matochkin Strait between the Severny and Yuzhny Islands of the Arctic (extreme north east of Europe) is 100km long but only 600m wide at its narrowest point. I had previously thought this was one island!
- Kara Strait between mainland Russia and Yuzhny Island is 56km wide.
- Øresund between Zealand in Denmark (containing Copenhagen) and Sweden, is 4km wide at one point.
- The English Channel (between England and France) is 34km wide and the world’s busiest international seaway.
- The North Channel between Scotland and Northern Ireland is 36km wide.
- The Strait of Gibraltar at the entrance to the Mediterranean (between Spain and Morocco) is 14.3km wide and 300-900m deep.
- The Bosporus (Istanbul, between Asia and Europe) is 704m wide at its narrowest point.
- The Dardanelles in northwestern Turkey are 61km long but 1.2 to 6km wide and 55-82m deep.
- The Strait of Messina is 3.1km wide between mainland Italy and the island of Sicily.
- The Strait of Bonifacio between the Mediterranean islands of Sardinia (Italy) and Corsica (France) is 11km wide.
- The Euripus Strait between mainland Greece and the island of Euboea (150km in length) is only 38 metres wide at its narrowest point!
- The Strait of Magellan at the southern tip of South America is 570km long and 2km wide at its narrowest point.
- The Yucatán Channel between Mexico and Cuba is about 196km wide.
- The Windward Passage between Cuba and Hispaniola (Haiti) is 80km wide.
- The Florida Straits between Cuba and Florida are about 160km wide.
- The Strait of Belle Isle is 125km long and 15-60km wide and separates Newfoundland and mainland Canada (Labrador)
- The Gulf of California in Mexico is 1126km long and 48-241km wide (actually a narrow bay rather than a strait)
- The Strait of Georgia between mainland western Canada and Victoria Island is 18.5 to 55km wide and 240km long.
- The Bering Strait between Alaska and Russia is 85km wide.