The Thames foot tunnel is a tunnel beneath the River Thames in London, between Rotherhithe and Wapping. Originally for pedestrians, it now is currently used by trains of the London Underground's East London Line. It was built by Marc Isambard Brunel in the 19th century.

A previous attempt at construction by Richard Trevithick has failed due to the difficult conditions of the ground. Brunel's approach in 1825 was to begin by digging a large shaft on the south bank at Rotherhithe. He did this by first building a brick cylinder above ground and then gradually sinking it by removing the earth beneath it.

Brunel devised the tunnelling shield to dig the tunnel, but work was slow, and workers fell ill from the poor conditions including Brunel himself. His son Isambard Kingdom Brunel took over as chief engineer, and when on 18 May 1827 the tunnel flooded, he used a diving bell to repair the hole at the bottom of the river. Following the repairs and the drainage of the tunnel, he held a banquet inside it.

The tunnel was flooded again the following year, 12 January 1828, and the project was abandoned for seven years, until Marc Brunel succeeded in raising sufficient money to continue work. Impeded by further floods and gas leaks (methane and hydrogen sulphide), it was not completed until 1842.

In 1865 it was bought by the East London Railway Company and adapted for trains, which ran out of Liverpool Street station.