Thracian and Greek Urdoviza (6th c. BC – 1st c.)
The area around today's Primorsko was inhabited by Thracians as early as the 6th century BC, while Greek colonists from Apollonia (Sozopol) used the southern Black Sea coast as a chain of port stations — one of them, known as Urdoviza, is located near the present-day neighbouring town of Kiten. A landmark archaeological find in the surrounding area is the Thracian megalithic sanctuary of Beglik Tash, located about 5 km north of Primorsko, along with traces of Hellenistic residential buildings along the coast.
Roman period (1st–4th c.)
After entering the Roman Empire, Urdoviza remained a small harbour station between Apollonia and Agathopolis (Ahtopol). Remains from this period include road infrastructure, a small bath and several graves — now on display in the Sozopol museum.
Middle Ages and Ottoman Empire (6th–19th c.)
During the Middle Ages the coastal settlements gradually lost their port role and the area became depopulated. Under Ottoman rule it was quiet and sparsely inhabited. The modern settlement was founded on 15 May 1879 under the name Kupriya (from Turkish köprü – "bridge") by four families of settlers from the Strandzha villages of Zabernovo and Bulgari (Urguri), who cleared the forest on the Kupryuburun peninsula.
Primorsko and the youth camps (1934 — today)
In 1934 the settlement was renamed from Kupria (Turkish for 'bridge') to Primorsko. In 1953 it acquired resort status, and by Decree No. 2190 of 16 October 1981 it was granted town status following its administrative merger with Kiten. During the socialist period, the Georgi Dimitrov International Youth Centre operated here, hosting hundreds of thousands of young people from over 50 countries. After 1989, Primorsko developed into a quiet family resort — a favoured alternative to the bustling Sunny Beach.