The Duke and Duchess of Cambridge's son is the first member of the UK Royal family to have his first birthday marked by a new coin.
The third in line to the throne and future king turns one on 22 July.
The design of the sterling silver piece was approved by his parents; his great-grandmother the Queen; and Chancellor George Osborne.
It bears the heraldic royal arms and the year 2014.
Prince George was photographed at the weekend walking with the help of his mother.
Shane Bissett, director of commemorative coin and bullion at the Royal Mint, said: "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.
"The choice of a silver coin is significant too, as the precious metal is closely associated with newborn babies...
"Crossing the palm of a newborn baby with silver is a way to wish them wealth and good health throughout their life, whilst the £5 coin is a favourite for royal celebrations."
The coins will be a limited mintage of 7,500 and will cost £80 each from the Royal Mint.
The heraldic royal arms incorporates the four quarterings of the royal arms, each contained in a shield, as well as a rose, thistle, leek, a sprig of shamrock and a crown.
It was originally created for the Queen and was last used on a coin struck for the British Exhibition in New York in 1960.
George's birth and his christening were also marked with commemorative coins.
A commemorative £5 coin is being produced to honour the first birthday of Prince George of Cambridge.