Diamond Beach is an unincorporated community and census-designated place (CDP)[7] located within Lower Township in Cape May County, in the U.S. state of New Jersey.

[10] According to the United States Census Bureau, Diamond Beach had a total area of 0.157 square miles (0.41 km2), all of which was land.

[11][12] Diamond Beach is home to many upscale townhouses and Seapointe Village, the site of a police substation that opened in 2013.

[13] The 2010 United States census counted 136 people, 71 households, and 46 families in the CDP.

[10] As of the 2000 United States census[4] there were 218 people, 103 households, and 73 families residing in the place.

The racial makeup of the CDP was 96.33% White, 2.29% African American, 0.92% Asian, and 0.46% from two or more races.

According to the Köppen climate classification system, Diamond Beach has a humid subtropical climate (Cfa) with hot, moderately humid summers, cool winters and year-around precipitation.

During the summer months in Diamond Beach, a cooling afternoon sea breeze is present on most days, but episodes of extreme heat and humidity can occur with heat index values at or above 95.0 °F (35.0 °C).

The plant hardiness zone at Diamond Beach is 7b with an average annual extreme minimum air temperature of 6.8 °F (−14.0 °C).