The lighthouse was built in the beginning of the 20th century and it began operating on September 15, 1905. The lighthouse keepers and their families lived in the lighthouse from 1905 until 1973. Later, only the employees who were on watch lived there. Slettnes was one of the last lighthouses in Norway to be fully automated. This occurred in 2005. In 1922 the lighthouse got a foghorn with a siren, which gave a signal every thirty seconds, helping in fog and bad visibility. During World War II the Germans used the lighthouse as an observatory position. Navy officers controlled the function of the light in the lighthouse. The lighthouse was only lighted when German convoys passed by. In Autumn 1944, when the Germans retreated, the lighthouse was blown up and all the houses in the region were burnt down by the German force. In the period between 1945 and 1948 new residential buildings were reconstructed, as well as a machine house (?), a boathouse, a quay and a lighthouse. The whole building designed by the architects G. Blakstad and H. Munthe-Kaas. The lighthouse is 39 meters high, has 9 stone steps and 139 steps inside. That is why Slettnes is the fifth highest lighthouse in Norway. The foghorn can be heard in form of a one to two tone signal with a range of 6 nautical miles. This was in use until 1985. In 1955 there was a radio beacon set up in the lighthouse, one year later the lighthouse was connected to the local electricity supply system. Today Slettnes is in “Kystverkets” property (the state-run coastal administration), and is run in cooperation with Gamvik community. Slettnes lighthouse was classified as an historical monument in 1998. In the summertime, Gamvik museum offers excursions and visits to the lighthouse and you will find a little café in the former house of the lighthouse keeper.