Grashaven is a yacht harbour located in Hoorn, North Holland, on the Markermeer. Situated at approximately 52° 38' N, 5° 3' E, it offers alongside moorings within easy walking distance of Hoorn's historic old town.

The marina provides a range of facilities including electricity, water, showers, restrooms, fuel, and Wi-Fi. Sanitary facilities have been recently renovated, and a small snack bar with a shop is on site.