Redcar's RNLI lifeboat was called to East Scar rocks in Saltburn on Saturday when three teenagers became stranded.
A spokesman said it was the latest in a spate of incidents in the area, with 18 people rescued so far this year.
Redcar and Cleveland Council has now said it will put additional signage on the beach, warning of the danger.
Lifeboat volunteers on Teesside have warned people not to get caught out by the incoming tide after yet another rescue.