Hornsea Inshore Rescue chair Sue Hickson-Marsay said sea conditions 'were not even suitable for paddling' despite warm and dry weather on July 15, when the six 17-18-year-olds from Hull and Beverley got into difficulties.
The group were caught in a rip tide and quickly swept out before being thrown against the beach's groynes - sea defences which prevent erosion..
The three girls and three boys managed to reach safety before seeking help from the volunteer-run organisation's crew member on duty to treat a range of injuries including cuts, bruises, shock and breathing problems.
"They managed to reach our lookout and our lifeboatman and a paramedic dealt with them - there was initially some confusion over whether any more of the group were missing. They had some nasty cuts and grazes from the barnacles on the groynes.
"They were in a bad way - one girl had swallowed a lot of water and spent some time in the ambulance as her heart rate was high, and they were in shock. They were covered in cuts.
"The current was strong that day, conditions were rough and nobody else was even paddling. The rip tide came and they were pulled out quickly. The Yorkshire Air Ambulance landed because they were worried about 'secondary drowning' because of the water they could have inhaled."
Sue added that Hornsea Inshore Rescue are experiencing their 'busiest ever' year and warned of the dangers of the water.
"We've already had people on inflatables swept out this summer."