Ceramic fragments from the 5th-4th century BC have been found in the Potamya inlet south of the village, as well as anchors and metal casing of an ancient ships. The village was first mentioned in an Ottoman document in 1496; the population then consisted of only 16 Christian families, as the attacks of sea pirates had forced many to move to inland Strandzha. According to Austrian diplomat Wenzel von Bronjar who sailed near the village, in 1766 it had 17 houses and its population mainly engaged in wood export. According to another westerner, Enelholm, in 1824 it had 30 houses and was located somewhat inland, with only its pier on the coast. Again, the low population and the location is explained by the attacks of the CaucasianLaz pirates.
After the Balkan Wars, the village and the surrounding area were ceded to Bulgaria. According to the Mollov-Kafandaris Agreement of 1927, the entire Greek population of the village moved to Greece and was substituted with Bulgarian refugees from Eastern Thrace. In 1926, it had 68 households. The current name dates back to 1934; prior to that, the village was known as Galadzaki (in Greek) or Kalanca (in Turkish). The name Sinemorets is a direct translation of the Greek original, which is derived from γαλάζιος (galazios, "azure"). Since 1989, Sinemorets is officially a sea resort, and has developed rapidly after access to the border zone was allowed.