Coastguards reunited 30 children with their worried parents during a single day at Camber Sands.
The youngsters, aged between five and 13, were all reported missing at the sandy beach on the border of Kent and East Sussex on Wednesday.
Teams carried out numerous air, sea and shoreline searches for the children.
Senior watch manager Peter Legg said 20,000 people went to Camber during the day and up to 7,000 remained on the beach in the evening.
He said: "It has therefore been very easy for children who may be playing in the sea or even on the beach to become disorientated and separated from their families or friends."
The children were being reported lost throughout the day either to coastguards on the beach or by 999 calls, he said.
Coastguard rescue teams from Dungeness and Camber carried out numerous shoreline searches, the Rye Bay RNLI lifeboat and Pett Private Rescue Boat ran sea searches, and the coastguard fixed wing aircraft spotted some missing children from the air.
'Head for landmark'
Parents using the beach have been urged to ensure they know where their children are, and that their children know where they are.
People can make a note of where they are on Camber Sands, which is marked into sections by colours and letters.
Coastguards have also suggested that parents give their youngsters a landmark to head for.
Families can also seek help from a coastguard vehicle, which is on the beach every day during the summer holidays.