Rebecca is a Research Vessel who explores everything about the ocean.
She is great at giving facts and information about the ocean and once advised Theodore to let Walter the Whale return to his family. Rebecca is the leader of the "Salvage Team" and works with Theodore, Northumberland and Shelburne to find great things under the water. Rebecca has no trouble finding underwater treasures with her special sonar equipment. She and the Salvage Team once found and old ships bell. Theodore looks up to Rebecca because she always does everything close to perfect. She may had a crush on Theodore. Rebecca also has a grumpy side, which she showed when Benjamin Bridge keep her up all night with his loud snoring. But even though Rebecca is not perfect, she is always fun to explore with and is the tugs closest guide to the mysteries of the sea.
Rebecca had three different models from seasons one to two. In the early season one episodes, she was originally completely faceless & nameless until she originally started out with a grey colour, an all-white hull and no eyebrows in season one which was seen in the early season 2 episodes (ex. Theodore in the Middle, Whale of a Tug). In season two, her eyes were bigger and her eyebrows were thick and grey, and half of her hull was painted light blue and later she had smaller eyes and grey eyebrows.
- Rebecca's engine which makes her move was sold on ebay.
- Rebecca is based on Jacques Cousteau's famous research vessel, RV Calyspo.
- ERTL models (retired)