The new coin has been unveiled for the prince’s birthday on June 21.
It will be the first time the Duke of Cambridge will appear alone on an official coin struck by the Royal Mint.
The coin, created by designer and engraver Thomas Docherty, features his portrait set amid his royal cypher — the initial W — and the number 40.
Meanwhile, Queen Elizabeth II’s image, designed by Jody Clark, will be struck on the other side of the coin.
There will also be an inscription on the edge reading: “HRH the Duke of Cambridge”.
A limited edition two-coin set will also be released, featuring a 0.25-ounce gold celebration coin and a 1982 sovereign, from the year the prince was born.
The collection will also include a limited edition coin made of 5oz of fine gold to mark the occasion, with laser technology creating a “high-relief finish” to give Prince William’s portrait an enhanced 3D appearance.
“The elegant design … pays homage to the maturity and grace of the prince, who has become a senior member of the royal family, a devoted husband and a loving father of three, through the eyes of the world," said Clare Maclennan, director of commemorative coins at the Royal Mint.
“Marking this extra-special occasion, we have also struck a limited edition gold coin made with 5oz of fine gold and struck in high relief to elevate the artistry of the design.
“Our limited edition precious metal coins combine fine craftsmanship and rarity, making them an attractive keepsake for collectors and investors.
“The design strikes a balance between the fresh energy of His Royal Highness being a young dad with the ceremonial nature of his royal position," Mr Docherty said of the design.
“A three-quarter angle of the portrait creates a more dynamic portrait rather than a traditional side-on profile.
“I used certain clay-sculpting techniques on a digital platform to achieve the style needed for the design, to translate effectively from two to three dimensions.
“Using technology, we can now produce designs and sculptures with better efficiency compared to when I began my career 17 years ago.
“There’s a high level of skills and craftsmanship needed to sculpt designs. The tools are different but the principles remain the same.”