Sea Isle City is a city in Cape May County, New Jersey, United States. It is part of the 'Ocean City Metropolitan Statistical Area'. As of the United States 2000 Census, the city population was 2,835. Sea Isle City is located on Ludlam Island, which also contains part of Dennis Township.

As of the censusGR2 of 2000, there were 2,835 people, 1,370 households, and 794 families residing in the city. The population density was 497.5/km˛ (1,287.3/mi˛). There were 6,622 housing units at an average density of 1,162.2/km˛ (3,006.9/mi˛). The racial makeup of the city was 97.88% White, 0.28% African American, 0.39% Native American, 0.35% Asian, 0.04% Pacific Islander, 0.07% from other races, and 0.99% from two or more races. Hispanic or Latino of any race were 1.06% of the population.