Thronion (Ancient Greek: Θρόνιον) was an Ancient Greek city on the Illyrian coast, in the Bay of Vlorë on the southern Adriatic Sea. Although the earliest contacts appear to have been more pre-colonial activity rather than permanent settlement, an ancient, still archaeologically unproven tradition claims that the city was founded as a Locrian–Euboean colony on the fringes of the territory of the Amantes. Thronion was located to the south of the territory of Apollonia and in front of the Acroceraunian Mountains, the natural boundary between ancient Epirus and Illyria. Thronion was conquered by nearby Apollonia before 460 BCE.
Thronion has been identified with the site of Triport northwest of present-day Vlorë, Albania, where a large fortified port-town that was inhabited from the 6th century BCE to the 2nd century CE is found now partially submerged.