The Stoneybrook Community Pool Complex has three outdoor pools: an Olympic-sized swimming pool, a diving pool, and a wading pool. It also has a a snack bar, a playground, a first-aid station and locker rooms. The complex is located near Stoneybrook Middle School, within a five-minute walk.
The complex works on a membership system. It offers swim lessons and hosts a synchronized swim team, which is associated in some way with SMS (lessons are held during the fourth period of the SMS school day, and the team participates in the SMS Sports Festival). The synchronized team is separate from the SMS swim team, which presumably also practices at the complex, but this is not explained.
In Jessi's Gold Medal, Jessi and Mallory's gym class spends the end of the school year taking swimming lessons at the pool and Jessi is recruited for the synchronized swim team. Jessi's family also gets a membership at the complex for the summer.
It's unclear whether the complex is part of the Stoneybrook Community Center.