RNLI Redcar volunteers were called out after a fishing boat suffered mechanical failure.
As the lifeboat began towing the disabled craft back to the River Tees, the rescue scene was visited by a small pod of dolphins.
RNLI helmsman Dave Scott said: "They were obviously curious to see what we were up to."
The scene was was captured by the helmet-mounted video camera worn by one of the lifeboat crew.
Mr Scott said: 'It was an absolute privilege to see such a wonderful natural phenomenon.
"It's certainly the first time for many years they've been spotted in this area during a rescue."
A routine lifeboat operation off the coast of Teesside attracted some unusual onlookers.