Prince Charles dropped in on his son as part of his annual summer tour of Wales with the Duchess of Cornwall.
William, who is based in RAF Valley in his capacity as a search and rescue pilot, took his dad into one of the Sea King helicopters which his team uses for missions.
The 63-year-old also saw the 'ready rack' where rescue crews store their kit in the operations room and met some of William's colleagues.
But as a reminder that it was business as usual at the base, the team received a call for help just minutes before Charles' arrival.
William was on shift, but his commanding officer took his place on the mission to rescue a man in trouble in the hills.
After Charles had left RAF Valley, of which he is the Honorary Air Commodore, the commanding officer said William had worked hard, to progress in his post.
Wing Commander Mark "Sparky" Dunlop said: "He joined the squadron approximately two years ago and he's studied hard and has attained his operational captaincy and therefore has met the rigorous demands of that requirement.
"Like all other operational captains, he should be rightly proud of that achievement.
"It is an honour to have the station's Honorary Air Commodore visit us today and continue to show his interest in the station and it's also great that yet another father gets to find out how his son contributes to search and rescue, 24/7 365."