Isabelle is a cargo ship who visited the Big Harbour a few times. Not much is known about her.
- Season 2 - Theodore's Whistle (cameo), The Tugboat Pledge (cameo), Snorri the Viking Ship (cameo), and Emily the Vigorous (not named, does not speak, has Elo Echo and Olympia's superstructures)
- Her hull was previously used for Caroline, and was later used for Linda.
- Her superstructure was recycled from Margaree Pride, William B., and Margaret, and was later used for Annapolis.
- In Emily the Vigorous, Isabelle has Linda's superstructure for some unknown reason.
- Isabelle is seen in the intro.