The Queen has handed out awards at a reception for the Royal Life Saving Society (RLSS) more than 75 years after achieving her own medal in the pool.
She greeted volunteers and representatives of the drowning prevention charity at Buckingham Palace yesterday to mark its 125th anniversary.
The monarch, now 90, was 13 when she achieved her Life Saving Medal from the society, of which she is the patron.
Two photos of the Queen as a teenager, one showing her in the water rescuing another swimmer and a second with the medal pinned proudly on her swimming costume, were posted on the Royal Family's official Twitter feed.
The Duke of Edinburgh and Prince Michael of Kent, the charity's president, joined her as she presented three prestigious honours on behalf of the life- saving society.
Meanwhile, the Duchess of Cambridge has revealed Prince George loves dinosaurs and likes the T Rex because it is "the noisiest and scariest".
Kate was at the Natural History Museum in London for a children's tea party to bid farewell to one of the museum's best-recognised exhibits, the enormous skeleton of a Diplodocus.
Dippy, the 21.3 metre plaster-cast sauropod replica, is going on a UK tour - including a visit to Belfast's Ulster Museum.
Elsewhere, Prince Harry returned to the Caribbean paradise island of Barbuda where he once holidayed with his mother, Diana, Princess of Wales.
Harry arrived by helicopter on the sun-kissed island where, as a 12-year-old, he enjoyed a break in April 1997 with Diana, and his brother William, then 14, a few months before she died.
Harry was left looking uncomfortable when Antigua and Barbuda's prime minister invited him and girlfriend Meghan Markle to spend their "honeymoon'' in Antigua.