The strait links the Coral Sea to the east with the Arafura Sea and Gulf of Carpentaria in the west. Although it is an important international sea lane, it is very shallow (7 to 15 m water depth), and the maze of reefs and islands can make it hazardous to navigate. In the south the Endeavour Strait is located between Prince of Wales Island (Muralug) and the mainland. Shipping enters Torres Strait via the Adolphus Channel which joins to the Great Barrier Reef lagoon to the southeast. Strong tidal currents occur in the narrow channels between islands and reefs, and large submarine sand dunes migrate across the seafloor. Some 580 coral reefs, including the Warrior Reefs and Eastern Patch Reefs, cover a total area of 2,400 km2 (930 sq mi) in the region, as well as some of the most extensive seagrass beds in the world.
Several clusters of islands lie in the Strait, collectively called the Torres Strait Islands. There are at least 274 of these islands, of which 17 have present-day permanent settlements.
Over 6,800 Torres Strait Islanders live on the Islands and 42,000 live on the mainland.
These islands have a variety of topographies, ecosystems and formation history. Several of those closest to the New Guinea coastline are low-lying, formed by alluvial sedimentary deposits borne by the outflow of the local rivers into the sea. Many of the western islands are hilly and steep, formed mainly of granite, and are peaks of the northernmost extension of the Great Dividing Range now turned into islands when sea levels rose at the end of the last ice age. The central islands are predominantly coral cays, and those of the east are of volcanic origins. The islands are considered Australian territory and are administered from Thursday Island. There are several major policy and institutional frameworks in the Torres Strait region that support the sustainable use and management of marine resources while also protecting habitats, biodiversity and the traditional islander way of life. Most important of these is the Torres Strait Treaty entered into by Australia and Papua New Guinea in February 1985. The Treaty defines sovereignty and maritime boundaries in the area between the two countries. It guides decision makers on protecting the way of life and livelihood of traditional inhabitants, on managing the protection of habitats, and on sharing the commercial and traditional fisheries resources. The Treaty established a Torres Strait Protected Zone within which both nations manage access to fisheries resources. Each country exercises sovereign jurisdiction for resources on either side of the agreed jurisdiction lines.
The islands' indigenous inhabitants are the Torres Strait Islanders, Melanesian peoples related to the Papuans of adjoining New Guinea. The various Torres Strait Islander communities have a distinct culture and long-standing history with the islands and nearby coastlines. Their maritime-based trade and interactions with the Papuans to the north and the Australian Aboriginal communities have maintained a steady cultural diffusion between the three societal groups, dating back thousands of years at least.
Two indigenous languages are spoken on the Torres Strait Islands: Kala Lagaw Ya/Kalaw Kawaw Ya/Kawalgau Ya/Muwalgau Ya/Kulkalgau Ya, and Miriam Mir, as well as Brokan [Broken], otherwise called Torres Strait Creole. In the 2001 Australian national census, the population of the islands was recorded as 8,089, though many more live outside of Torres Strait in Australia.
Environmental issues facing the region include the risk of mining waste from the Fly River in southern Papua New Guinea, the impacts of global climate change and the sustainable management of natural resources.
The islands of the Torres Strait have been inhabited for at least 2,500 years and possibly much longer.
The first recorded European navigation of the strait was by Luís Vaz de Torres, a pilot who was second-in-command on the Spanish expedition led by navigator Pedro Fernandes de Queirós who sailed from Peru to the South Pacific in 1605. After Queirós's ship returned to Mexico, Torres resumed the intended voyage to Manila via the Maluku Islands. He sailed along the south coast of New Guinea, and may also have sighted the northernmost extremity of the Australian mainland, however no specific records exist that indicate he did so.
In 1769 the Scottish geographer Alexander Dalrymple, whilst translating some Spanish documents captured in the Philippines in 1762, had found Luís Vaz de Torres' testimony proving a passage south of New Guinea now known as Torres Strait. This discovery led Dalrymple to publish the Historical Collection of the Several Voyages and Discoveries in the South Pacific Ocean in 1770–1771, which aroused widespread interest in his claim of the existence of an unknown continent. It was Dalrymple who named the strait after Torres. Dalrymple was bitterly disappointed that it was James Cook and not he who was appointed commander of the expedition that eventually led in 1770 to the British encounter and charting of the eastern coastline of Australia.
In 1770 Cook claimed the whole of eastern Australia for the British Crown, and sailed through the strait after proceeding up the eastern coast of the continent.
In 1823 Lieutenant John Lihou, then Master of HMS Zenobia, was on passage from Manila to South America and chose a route through Torres Strait. This was the first occasion a ship was navigated through Torres Strait from west to east. It was also the first occasion a ship was navigated through the Coral Sea from Torres Strait, south-eastward to the southward of New Caledonia. Lihou saw Sir James Saumarez' Shoal (now Saumarez Reefs) on 27 February and named the reef system after Vice-Admiral James Saumarez. On this same trip, Lihou discovered the Lihou Reef and Cays and Port Lihou.
The London Missionary Society arrived on Erub (Darnley Island) in 1871. Although some of the Torres Strait islands lie just off the coast of New Guinea, they were annexed in 1879 by Queensland, then a British colony. There was an important pearling industry from the 1860s until about 1970 when it collapsed in the face of competition from the plastics industry. Pearl-shelling was responsible for the arrival of experienced divers from many countries, notably Japan.
In 1978 an agreement between Australia and Papua New Guinea determined the maritime border in the Torres Strait.
Torres Strait is mentioned in Jules Verne's Twenty Thousand Leagues Under the Sea as a dangerous strait where the submarine, the Nautilus, is briefly stranded.
The people of the Torres Strait have a unique indigenous culture, which has been the centre for anthropological work completed by Cambridge University's Alfred Haddon in 1898 and Australia's Margaret Lawrie from 1960 to 1973.
Due to proximity to the Papua New Guinea mainland, the northern Torres Strait islands experience occasional asylum seeker arrivals from across the Strait. A total of ten asylum seekers from Papua New Guinea were detected in each of 2012 and 2013.
In 2016 the Australian Federal Police were tipped off by residents of Prince of Wales Island that men from Sydney were attempting to buy a boat to reach Papua New Guinea in order to leave Australia without a passport.
The two routes through the Strait are: