The boat was parked in the driveway of a house at Springholm Village, situated next to the A75, and is described as blue, about 3.6 metres long and 1.6 metres wide and made from fibreglass.
It was stolen between 9:30 pm last Thursday and 5 pm on Friday.
Constable Anna Clark, based in Castle Douglas, said “This is a brazen theft and I would appeal to anyone who lives in or was passing through Springholm to think back and remember if they saw anything suspicious in the village on Thursday or Friday.
“Alternatively, do you remember following the boat along the A75 or did you capture it on a dash cam?”
Anyone with any information should contact Police Scotland on 101 quoting incident 2979 of 28th September 2018.
