Previously unseen pictures show two future kings enjoying the fresh air at the Royal Family's much-loved Norfolk retreat.
They form part of a collection of photographs and letters which belonged to Dr Frederick Douglas Selmes Jackson, who was the doctor in attendance at Sandringham, which is being sold at auction.
Prince Edward (Edward VIII) and his younger brother Prince Albert (George VI) are seen shooting, fishing, skating and playing golf on the pine-fringed estate near King's Lynn.
Pictures also show King Edward VII, King George V and Queen Mary out shooting.
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The doctor's archive, which dates back to 1904 - 06 also includes letters signed by the then young princes, who were fond of their physician.
In December, 1906 Prince Albert (George VI) wrote to thank him for the gift of a box of golf balls.
"Dear Dr Jackson, Thank you very much for the nice box of electric golf balls," he wrote.
"I like them very much. I wish you would come down and have a game of golf.
"Your sincere friend, Albert."
The collection also includes letters Dr Jackson wrote to his mother, telling her of his encounters with the royals.
"Prince Albert recounted many amusing yarns on the way round," he said after a round of golf with the future monarch.
In another, he adds: "I am going to have nursery tea with the York Cottage kiddies.
"The doctor has never before been fortunate enough to get an invitation."
Dr Jackson, who died in 1942, was also invited out on royal shoots at Sandringham.
After one, he wrote: "After the first drive the Prince of Wales came up to me and shook hands.
"I walked along with him for about a quarter of an hour and talked of shooting, golf etc. The shooting was A1 - well over 2,000 pheasants."
The collection is expected to fetch £2,500 when it comes under the hammer at Bonhams in Knightsbridge on Wednesday, March 29 (1pm).
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