And more than two in five in this age range have not been on a plane, the poll by travel agent www.sunshine.co.uk found.
Based on responses from 1,399 children aged eight to 15, the survey also showed that 52 per cent had only been to one other country.
Also, 32 per cent had never built a sandcastle on the beach and 37 per cent had never seen a crab.
Asked for a favourite overseas holiday destination, 34 per cent of the children opted for a Disney resort.
Sunshine.co.uk co-founder Chris Brown said: "I think it's incredibly sad that so many children haven't paddled in the sea. It's something every young person should have experienced."