The Sigri Lighthouse is located on the island of Nisiopi, also known as Megalonisi. It is located at an altitude of 53 meters above sea level and is visible from a distance of 20 nautical miles. The height of its tower is 20 meters, and its focal height is 55 meters.The lantern was made in 1861 by the French company Faron.

After the liberation of Lesvos (1912), it was handed over to the Greek Lighthouse Service on January 12, 1916. The existing equipment was repaired and the lighthouse was manned by lighthouse keepers. In 1930, new lighting equipment was ordered from the English company Chance, which operated with an 85mm diameter oil lamp. The optical, which rotated with the help of a manual clock mechanism, consisted of 16 lenses. In 1931 the building facilities were overhauled.

After World War II the lighthouse was badly damaged, and provisionally repaired. In 1957 the lighting equipment was dismantled, and transferred to the Lighthouse Service for general repair.

Since 1991 the lighthouse has been operating with the old optical rotation mechanism and with the old optical, in which an electric lamp has been placed.

It is listed in the Hellenic Lighthouse with the number AEF 7130. It is placed in a position of 39°12.8′ N, 25°50.0′ E, and has a characteristic 7” light and 23” darkness, i.e. a period of 30 seconds.