North Sea is a hamlet and census-designated place (CDP) in the Town of Southampton in Suffolk County, on the South Fork of Long Island, in New York, United States.

[2] It is served by the North Sea Fire District, which operates in adjacent areas as well.

[2][3] As of the census[5] of 2000, there were 4,493 people, 1,880 households, and 1,210 families residing in the CDP.

There were 3,265 housing units at an average density of 265.2 per square mile (102.4/km2).

28.2% of all households were made up of individuals, and 10.0% had someone living alone who was 65 years of age or older.