Visitors to the coast during the Easter holidays are being urged to be careful after a number of people had to be rescued after getting cut off by spring tides.
The RNLI has rescued eight people from Sully Island off the coast of Barry, Vale of Glamorgan, in the past week which is an area with fast-rising tides and akin to "a great big bath filling up rapidly and draining rapidly".
The charity said a survey by Bangor University suggested about 15% of people had been cut off by the tide.
It also said almost 8% of callouts in Wales over the past decade were for people getting cut off by the tide – more than double the UK average.
Once the causeway to Sully Island is submerged, people cut off may be stranded for up to six hours.
This means some may be tempted to swim back, which is being described as "a dangerous decision" in fast-moving water.
