Het Dok Nieuwolda is a small municipal marina in the village of Nieuwolda, situated on the Termunterzijldiep in the province of Groningen.

The harbour offers space for around ten boats, with additional mooring places along the banks of the Termunterzijldiep itself. The marina lies on the through waterway connecting Scheemda, Midwolda (Blauwestad), and Termunten, with onward access to Delfzijl.

Drinking water is available at the harbour. Toilets and showers can be found at the nearby Eetcafé de Brug. The village of Nieuwolda also has a supermarket and bicycle hire.