Staff from the Canal & River Trust, spotted the animal, likely to be a bottlenose dolphin, trying to head up the Gloucester & Sharpness Canal, and worked with local lifeboat service Severn Area Rescue Association (SARA) to coax it back out to sea.
While not unheard of, dolphin sightings this far inland are rare.
Mike Nash, from the Canal & River Trust's Sharpness Port team, said: “I've seen dolphins in the entrance to Sharpness before but never inside, and we had to do everything we could to stop it heading up the canal. The dolphin seemed ok during the day and caused a bit of interest, then two of SARA's rescue boats from Sharpness came in to assist coaxing the dolphin out, which we were very grateful for.”
Laura Mullholland, ecologist at the Canal & River Trust, said: “Sightings of dolphins on the country's inland waterways are very rare, and it's a great thing that we were able to get this one back out to sea, where dolphins belong. It's likely that the animal got a bit disoriented following some fish, but as nice a place as Gloucester is to visit, it's definitely for the best that it didn't make the trip.”