resort town, one of the best-known coastal resorts in Istria, republic of Croatia, situated on the Kvarner (gulf) of the Adriatic Sea. The town's name derives from the old Benedictine opatija (“abbey”) of San Giacomo al Palo, situated in the main park. Besides remains of medieval walls and the town gate, there are striking villas built by Austrian and Hungarian nobility in the 19th century.

Austrian before World War I, Opatija was ceded to Italy in 1919 and returned to Yugoslavia after World War II. The Opatija Riviera developed as a tourist and vacation centre in the latter half of the 19th century, stimulated by the Trieste-Rijeka railway in 1873; the resort still draws great numbers of tourists annually. Pop. (2001) mun., 7,851.