[9] The Belvidere High School County Seaters[2] athletic teams compete in the Valley Division of the Skyland Conference, which is comprised of public and private high schools in Hunterdon, Somerset and Warren counties, and operates under the supervision of the New Jersey State Interscholastic Athletic Association (NJSIAA).

[13] Interscholastic sports offered include football, baseball, softball, basketball, cross country, swimming, cheerleading, golf, wrestling, field hockey, and soccer.

[18] The 1989 team finished the season with a 9-2-2 record after a scoreless tie with Haddonfield after regulation and overtime in the Group I championship game.

[20] The boys wrestling team won the North II Group I state sectional championships in 1996 and 1999-2001.

[24] The team won the North I, Group I state sectional title in a shootout after overtime ended in a 2-2 tie with Cresskill High School.