Costinesti is a commune and resort in Constanta County, Northern Dobruja, Romania, located on the shore of the Black Sea, about 30 kilometres (19 mi) south of the county seat, Constanta. It consists of two villages: Costinesti and Schitu.

In the 1960s, it evolved from a small fishing village to a summer destination, most popular with young people and students. A hotel and several villa complexes were built in the Communist era, and featured varying degrees of style and comfort. Since the Romanian Revolution of 1989, some of them have been modernized, and private construction, especially to the north of the resort, has taken off.

The resort also has a small inland lake, around which there are several lodges.

Lying off one of the northern beaches is the shipwreck of the Greek cargo ship E Evangelia (originally the UK refrigerated cargo ship Empire Strength). She was beached there in 1968 and is quite popular with tourists.

Nightlife is centered mainly around the two discos (Ring and Tineretului), in which, during the summer months, concerts are held nightly by the most popular bands from across Romania. Because Costinesti is mostly frequented by youngsters, the atmosphere tends to be livelier than in the other Black Sea resorts.

Costinesti is accessible by either rail or road. There are two CFR railway stations within the resort (South Costinesti - Tabara, North Costinesti), and the town is connected to the main E87 road which runs north to Constanta and south to the Bulgarian border.

At the 2011 census, Costinesti had 2,713 Romanians (98.65%), 3 Hungarians (0.11%), 13 Roma (0.47%), 8 Turks (0.29%), 13 others (0.47%).