The 5-pound coin, which was approved by the Duke and Duchess of Cambridge, the queen and Chancellor George Osborne, has the heraldic royal coat of arms and the year 2014 inscribed on the face.
Only 7,500 will be minted and will cost 80 pounds ($135) each.
"As Prince George of Cambridge reaches the significant milestone of turning one year old, we felt there could be no more fitting design to mark the first birthday of our future king than the royal arms -- the arms of the monarch -- minted in honour of the future heir to the throne," said Shane Bissett, the director of commemorative coin and bullion at the Royal Mint.
Prince George turns one on July 22.
Celebrity Families of 2014 [PHOTOS]