A spokesperson said: “Tombstoning has hidden dangers. Water depths change and there could be hidden debris. Jumping into water can also cause cold water shock.
“Every year people need rescuing, suffer serious injuries, or even die.
“Keep yourself and your mates safe. Don’t jump into the unknown.”
Tombstoning is the act of jumping in a vertical posture into water from a high platform.
The title was adopted because of the way a person falls and plunges into deep water, in a similar way a stone would.
According to the Maritime and Coastguard Agency, the Coastguard has dealt with more than 200 tombstoning incidents, with 70 injuries and 20
deaths, since 2004.
Issues that those tombstoning potentially face include water being shallower than it appears, submerged objects like rocks not being visible, shock of cold water making it difficult to swim, and strong currents rapidly sweeping them away.