When the canal was dug, a 157 m long sluice with an 11 m wide swing gate at both ends was built at its beginning. It took 45 minutes to move the ship with it. The purpose of the lock was to even out large differences in water levels during the Minija floods.
It is the only lock in Lithuania that has been declared a technical monument. Lankupiai lock is still occasionally used for its intended purpose. As the historian prof. dr. Vygantas Vareikis, perhaps the Klaipėda Canal, is not equal to other canals in the world excavated at about the same time, but it is the only waterway of this type and length with a lock in Lithuania.