Smuggling tunnels are secret passages used for the smuggling of goods and people. The term is also used where the tunnels are built in response to a siege.

The Sarajevo Tunnel operated during the Siege of Sarajevo as a passage underneath the no-man's land of the city's (closed) airport, providing a vital smuggling link for the beleaguered city residents. Guns were smuggled into the city and people were smuggled out. After the Bosnian War, the Sarajevo Tunnel Museum was built onto the historic private house whose cellar served as the entrance to Sarajevo Tunnel.

More than 70 tunnels were used to smuggle people under the Berlin Wall between West Berlin and East Berlin.

A 700-meter smuggling tunnel with a narrow gauge railway was revealed in July 2012 between Uzhhorod, Ukraine, and Vyšné Nemecké, Slovakia, at the border of Schengen Area. The tunnel used professional mining and security technologies. It was used primarily for smuggling of cigarettes.

Many villages on the southern coast of England have a local legend of a smugglers' tunnel, although the entrances to most of the actual smugglers' tunnels have been lost or bricked up.

Some tunnel stories turn out to be plausible, such as the tunnel at Hayle in Cornwall, which seems to have been built specifically for smuggling. However, tunnels often double as a storm drain or some other functional channel, or else as an extension of a natural fissure in the rock as at Methleigh and Porthcothan, but tunnels and caches (both wholly excavated and formed by extending natural formations) are more commonplace where covert landings in areas with few sheltered beaches exposed smugglers to the attentions of the Revenue Men.

While many sites are rudimentary, extensive workings have been found which show evidence of skillful excavation, strongly implying the assistance of tin miners.^{[citation needed]}

Beith in North Ayrshire was a notorious haunt of smugglers at one time, and legend has it that a tunnel ran from the town centre down to Kilbirnie Loch.^{[citation needed]}