The Red Sea is a seawater inlet of the Indian Ocean, lying between Africa and Asia. The connection to the ocean is in the south through the Bab el Mandeb strait and the Gulf of Aden. In the north, there is the Sinai Peninsula, the Gulf of Aqaba, and the Gulf of Suez (leading to the Suez Canal). The Red Sea is a Global 200 ecoregion. The sea is underlain by the Red Sea Rift which is part of the Great Rift Valley.

The Red Sea has a surface area of roughly 438,000 km² (169,100 mi²). It is about 2250 km (1398 mi) long and, at its widest point, 355 km (220.6 mi) wide. It has a maximum depth of 2211 m (7254 ft) in the central median trench, and an average depth of 490 m (1,608 ft). However, there are also extensive shallow shelves, noted for their marine life and corals. The sea is the habitat of over 1,000 invertebrate species, and 200 soft and hard corals. It is the world's northernmost tropical sea.

The International Hydrographic Organization defines the limits of the Red Sea as follows:

On the North. The Southern limits of the Gulfs of Suez [A line running from Ràs Muhammed (27°43'N) to the South point of Shadwan Island (34°02'E) and thence Westward on a parallel (27°27'N) to the coast of Africa] and Aqaba [A line running from Ràs al Fasma Southwesterly to Requin Island (27°57′N 34°36′E / 27.95°N 34.6°E / 27.95; 34.6) through Tiran Island to the Southwest point thereof and thence Westward on a parallel (27°54'N) to the coast of the Sinaï Peninsula].