Hallenbad Sundern is a municipal indoor pool used for scuba training, skills refreshers, and equipment checks in calm, weather-proof water. The complex combines an adjustable-floor swimmer's pool with a dedicated diving basin, so you can move from shallow drills to deeper practice without leaving the venue. Access is operator-managed and tied to opening hours plus booked school, club, or course windows. It is a strong year-round option when you want controlled conditions instead of open-water variability.