Those who have an interest in all things nautical will enjoy Donaghadee Harbour. It's a nice place to go for a wander by the water's edge and admire some boats.
If you're staying a while in Donaghadee, Donaghadee Harbour is a good place to kick off your sightseeing. This place for ships to anchor is one of many attractions worth checking out here. Bangor Marina, Bangor Castle, and Bangor Abbey are also ready to be explored close by.