Dartmouth is a giant cable ship who won the attention of all the tugboats when he first arrived in the Big Harbor. Digby showed him good places to lay cables.
Dartmouth loves to work with Theodore and Digby and is very nice. He and Theodore are part of A group with Digby that Digby calls The Three Good Buddies.
Dartmouth first appeared in Season 4 in Digby's Disaster and in Dartmouth Says Goodbye as his last appearances.
- Dartmouth is named after the former city of Dartmouth, Nova Scotia, which lies on the eastern shore of Halifax Harbour. Dartmouth's municipal government was amalgamated into the Halifax Regional Municipality in 1996, but the area still retains its original name.