It was recently revealed that Wills and Kate are taking steps to ensure their children become good swimmers.
The Duke of Cambridge revealed he has a "family of swimmers" to Eileen Fenton, (the first woman to finish the English Channel race), according to the Press Association (via Express).
"He said that he and his wife make sure the children can swim and they all go and they swim quite well," Ms Fenton recalled after being honoured with an MBE by the royal at an investiture ceremony at Buckingham Palace.
Ms Fenton also recalled how Princess Margaret and Queen Elizabeth II were also avid swimmers.
"I can remember seeing when the Queen was young and her sister Princess Margaret - we used to see them swimming in pictures," she said, noting how Prince William told her the Royal Family were all able to swim.
In 1939, the then Princess Elizabeth and Princess Margaret participated in a swimming competition. At age 13, Her Majesty won a Life Saving Medal from the Royal Life Saving Society.
In February this year, the Duchess of Cambridge was seen swimming with Princess Charlotte and Prince George at a luxury hotel complex in Norfolk near their country home, Anmer Hall, according to the Daily Mail. A source noted the children were swimming unaided and even attended a race organised by their mother.
"Both the children swam unaided and were super confident," the source said. "They went under the quite forceful jets in the water."
"Kate politely asked us if it was ok for them to switch it on," the witness continued. "They were doing little jumps off the side into her arms."
"Kate did not move from their sides...George did ask to go outside to use the hot tub but she said 'No'."
As both William and Kate are advocates of an active and outdoorsy lifestyle, it's no surprise their children have a love of physical activity.