Jachthaven Termunterzijl is a tidal harbour on the Termunterzijldiep, situated behind the protective coastal dike on the Groningen coast near the Ems-Dollard estuary.

It is one of the smallest and most traditional sluice harbours along this coastline, offering around 65 berths in an outer tidal basin plus an inner harbour. Maximum draft is 180 cm, and vessels longer than 15 metres should arrange berthing in advance.

The harbour monitors VHF channel 31. The setting is quintessentially Groningen: flat, wide-sky farmland stretching behind the dike, with the historic lock "Boog van Ziel" (1725) nearby and the village of Termunten just a kilometre inland.

Few visiting yachts make the journey here, making it a rewarding off-the-beaten-track stop for those exploring the Dutch Wadden coast by water.