In the autumn of 2020 a large population of the Maritime gardensnail Cernuella cisalpina (Rossmässler, 1837) was encountered along an unpaved road east of Oosterend 65 on Terschelling, one of the Wadden Sea islands of the Netherlands. This exotic land snail was already known from three other Wadden Sea islands: Texel, Vlieland and Ameland.