Glaucus and Nireus are considered Simi's children. Glaucus was an excellent naval-builder and skillful sponge-fisher. He was the one who manufactured "Argo", the ship which carried the Argonauts to Colchis. According to the myth, Glaucus was immortal, as he ate the herb of immortality, on the island of Makari. He could swim for days, or descended to the bottom of the sea for many hours, without ever becoming tired. According to mythology, Glaucus was a fortune teller and a voluptuous person. He divorced his wife, Simi, for Edna, only to marry Skilli, who was transformed into a monster by Êirke, because Glaucus did not return her love. It is said that he was once in love with Ariadne, the wife of Thesseus. Ariadne informed her husband about Glaucus's behaviour and Thesseus punished him. In the Homeric years, the island of Simi was ruled by Nireus, the son of Harokopos and Aglaia, the rulers of Achaia. Nireus was a good ruler who expanded his kingdom to Knidia Karea, the ruler of the sea at that time. He participated in the Trojan War with three ships, when Rhodes had nine ships, and he remained loyal to Agamemnon, until the day he died, fighting the Troians, by the side of his brave soldiers. Lucianus mentions that a statue of Nireus was found in Syria, a fact confirmed by Dianus, while contemporary archaeologists claim that his tomb is situated at Pondikokastro.

After the end of Nireus' rule, Simi came under the command of the Dorians, being a part of the Six Dorian Cities, while the people of the island supported the Lacaedemonias in the Peloponnesian War. On the ruins of Simi's ancient acropolis the Byzantines built new buildings, while their example was followed by the Knights of Rhodes, when they conquered Simi, in 1309. When the Turks occupied the island in 1523, the people of Simi had extra privileges due to their progress in naval-production. The locals lost their privileges due to their participation in the Greek Revolution. After the Italian-Turkish War in 1912, Simi came under the command of the Italians until 1945, while it was united with Greece on 7 May 1948 by a protocol approving the annexation of the Dodecanese islands to the Motherland.