Memmert is a tiny, uninhabited island visible from the western tip of Juist, lying about eight kilometres to the south-southwest in the Wadden Sea. It is a strict nature reserve — a single warden lives on the island during the breeding season — and has been protected since 1907, one of the earliest official bird reserves in Germany.
The island cannot be visited freely; the only way to see it is by booking a boat trip from Juist or from the mainland that circles Memmert without landing. The reward is sight of the largest grey seal colony in Lower Saxony — several hundred animals haul out on the beaches — and, in summer, a vast concentration of breeding seabirds.