Plavje (ˈplaːu̯jɛ; Plavia Monte d'Oro) is a village in the City Municipality of Koper in the Littoral region of Slovenia. It is located on the northernmost edge of the Istrian peninsula, on the border with Italy, on a small hill overlooking the Gulf of Trieste.
It has a small border crossing with Italy, connecting it with the nearby village of Belpoggio in Noghere (Beloglav), south of Trieste, which used to be a hamlet of Plavje (until 1954). Since Slovenia's accession to the European Union and the Schengen area, customs and immigration checks have been abolished at the Italian-Slovenian border.
Plavje is located on a small slope overlooking the Gulf of Trieste and Koper Bay. It is located on the border with Italy, which runs on the northern edge of the village. It has good road connections to Koper and Trieste because it is located above the highway connecting the two cities.
It enjoys a mild climate, save for the strong bora wind that frequently blows in the winter.
During most of its history, Plavje was part of the municipality of Muggia. From the 14th century until 1797 it was part of the Republic of Venice. Between 1805 and 1813, it was under Napoleonic French rule. After Napoleon's defeat, it was included in the Austrian Empire, as part of the Margravate of Istria within the Austrian Littoral.
According to the last Austrian census of 1910/1911, the village had 771 inhabitants, of which 78.3% were Slovenes and 18.5% Istrian Italians. The rest were mostly Croats and Italians from the Kingdom of Italy.
In 1907, a Slovene language primary school was opened in the village. In November 1918, the village was occupied by Italian troops and officially annexed to Italy in 1920. During World War II, partisan anti-Fascist guerillas were active in the area. The first cell of the Liberation Front of the Slovenian People in Slovenian Istria was organized in Plavje in early December 1941. After the Italian armistice in September 1943, it was occupied by Nazi German forces and included in the Operational Zone Adriatic Coast.