There was a fifty percent increase - from 36 to 54 - in the number of children under the age of fourteen who drowned in 1999, when compared with the previous year, the most recent figures from the Royal Society for the Prevention of Accidents show.
Half of all the deaths were in rivers or streams, RoSPA said.
The Amateur Swimming Association has issued advice to parents as thousands of families prepare to set off for summer holidays.
Get Safe for Summer
An ASA spokesman said: "People will venture to places many have never been before, near the seaside, or at a hotel or holiday village with a swimming pool, perhaps a lake or river may feature prominently in this holiday picture.
"Tragically however, figures suggest that someone will not return from the holiday destination, due to drowning.
"Spotting dangers, taking safety advice and knowing what to do faced with a dangerous situation can help prevent these circumstances arising in the first place."
The Get Safe For Summer campaign, also urges parents not to be lulled into a false sense of security if their child can swim.
The ASA's Amanda Church said: "When someone gets into difficulty in the water, there is very little time in which to act.
"It is absolutely vital that parents and children are aware of the potential dangers, and constant vigilance is demanded especially when very young children enter the water, even seemingly harmless shallow water."
The Amateur Swimming Association is the UK's Governing Body for Swimming.