Indispensable Strait is a waterway in the Solomon Islands, running about 200 kilometres (108 nmi; 124 mi) northwest-southeast from Santa Isabel to Makira (San Cristóbal), between the Nggela Islands and Guadalcanal to the southwest, and Malaita to the northeast.

Indispensable Strait is part of the navigation route for merchant shipping from Torres Strait to the Panama Canal. It is one of three major routes for merchant shipping through the Solomon Islands; the routes are the Bougainville Strait and Indispensable Strait, which link the Pacific Ocean, Solomon Sea and Coral Sea; and the Manning Strait that links the Pacific to New Georgia Sound, which is also known as ‘The Slot’, through which Japanese naval ships resupplied the garrison on Guadalcanal during the Pacific War.

The strait was first recorded on European maps after it was encountered by Captain William Wilkinson in the merchantman Indispensable in 1794.

• Findlay, Alexander George (1877) A Directory for the Navigation of the South Pacific Ocean: With Descriptions of Its Coasts, Islands, Etc., from the Strait of Magalhaens to Panama, and Those of New Zealand, Australia, Etc., Its Winds, Currents, and Passages. (R. H. Laurie).
• Josef Rick; Rüdiger Wolfrum; Ursula E. Heinz; Denise A. Bizzarro (1991). Title Law of the sea at the crossroads. Duncker & Humblot. ISBN 9783428472406.

9°00′S 160°32′E / 9.00°S 160.53°E / -9.00; 160.53