Jachthaven De Mars is a family-run marina and campsite located at Marsweg 6 in Lathum, Gelderland, situated within the recreation area of Rhederlaag.

The site serves as a water-access point with berths available in both an east and west harbour, with mooring fees varying by location and boat length.

The marina sits amid the extensive waterways of Rhederlaag, offering opportunities for swimming, fishing, surfing, and sailing. A ferry crossing the IJssel provides easy access to the Posbank and surrounding countryside.

Day trips to Arnhem, Doesburg, and Doetinchem are also within reach, and the area is well suited for cycling and hiking.