Lifeguards have pulled 15 people to safety after a flash rip current swept them quickly out of their depth.
The group, including children and teenagers, were on Perranporth beach in Cornwall at low tide at 12.15pm today.
A two to three-foot swell broke into shallow water, creating a shore dump.
The 13 bodyboarders and two bathers were between red and yellow flags to the north of the rip current when a sudden flash rip opened up and quickly swept them out of their depth.
Four RNLI lifeguards who were patrolling the flagged area immediately spotted the 15 in danger.
Three took to rescue boats and one grabbed a rescue tube to bring back 13 of the stricken people, including two children.
Back-up arrived and the team from the lifeguard unit at the top of the beach launched the Inshore Rescue Boat to pick up the remaining two.
Simon Peppler, RNLI lifeguard supervisor, said: "Low tide exposes the rip currents on Perranporth beach and the RNLI lifeguards are always extra vigilant around this time, with four lifeguards on patrol at the water's edge.
"It's essential that people stay between the red and yellow flags. Should anyone need the lifeguard's assistance, they can respond immediately and avert a serious incident. Please also try and listen to what the lifeguards are saying, because the waves are breaking so close to shore, it's fairly easy to get out past them, but harder to get back in.
"Some water users are venturing too far out and then finding themselves in difficulty."