The Middletown Swim and Tennis Club is a members-only organization located on 10 acres on Harmony Road. It opens on weekends at the end of May, going to a full-day schedule at the end of June. It features tennis courts, four swimming pools, bocce ball, volleyball and other activities, including day camp. Applications for membership are available through the township.
The Middletown Swim and Tennis Club is home to the Middletown Mariners, the Middletown Swim and Tennis Club's swim team, which was the 2010 Monmouth County League swimming champ.