Harry Potter And The Philosopher’s Stone was first published in the UK in 1997 by Bloomsbury Publishing.
The Hogwarts Express collectable coin is part of a wider collection celebrating the anniversary.
It is also the final individual 50p coin to have Queen Elizabeth II’s portrait appear on the obverse side of the coin.
Harry Potter Hogwarts Express coins launched by the Royal Mint
The collection also features individual coins of Harry Potter, Professor Dumbledore and Hogwarts School of Witchcraft and Wizardry.
The first two coins in the Harry potter collection feature the late Queen Elizabeth II.
However, the portrait will change to King Charles III for the final two coins which is rare for a series, the Royal Mint has explained.
Rebecca Morgan, director of collector services at the Royal Mint said: “A change in portrait makes this collection a highly sought after one.
“For 70 years, Queen Elizabeth II’s portrait has appeared on every official UK coin struck by the Royal Mint.
“This collection of coins serves as a permanent reminder of the fascinating transition from Britain’s longest reigning monarch to His Majesty the King’s first appearance on UK coins.”
Jim Kay's illustrations have been reproduced in colour on some of the coins and have been created by combining traditional minting techniques with technology.
A "latent feature" that rotates in the light to reveal the iconic lightning bolt and the number 25 to mark the anniversary will also be seen on many coins.
The intricate design was imprinted by a laser by the Royal Mint onto its coin-making tools in order to ensure its accuracy.
How much will the Harry Potter Hogwarts Express coins cost?
The prices for the magical coins range from £11 for a brilliant uncirculated 50p denomination version to £5,215 for a £200 denomination gold coin.
The coin series has been created in partnership with Bloomsbury Publishing, The Blair Partnership and Warner Bros, Consumer Products.
Mandy Archer, editorial director at Bloomsbury Children’s Books said: “We are delighted to see the latest coin in the Royal Mint’s Harry Potter collection.
“Jim Kay’s evocation of the Hogwarts Express instantly whisks you away to platform nine and three-quarters – the very start of Harry’s magical journey.
“It’s a joy to see his stunning book illustration so skillfully and beautifully rendered on a new silver anniversary coin.”