Transport for London (TfL) said the limited edition cards - which display the message, "20 years shaping life in London" – are available from all Tube stations in Zone 1, as well as visitor centres and selected Oyster ticket stops.
The launch of the Oyster card on 30 June 2003 revolutionised the way passengers paid for London Underground and bus journeys in the capital.
They allowed passengers to add money to a smartcard for pay-as-you-go travel in London for the first time, avoiding the need to queue to buy paper tickets or hand over cash to bus drivers.
Oyster cards led to the introduction of payments by contactless cards and devices in London, as well as pay-as-you-go technology in many cities around the world.
Nearly 17 million Oyster cards were used in the past 12 months.
Image credit: Transport for London
TfL chief technology officer Shashi Verma said: "We're excited to be celebrating 20 years of the Oyster card as a world-leading innovative way to travel.
"Customers have loved the convenience of pay-as-you-go travel and we are immensely proud to celebrate two decades of the Oyster card making travelling in London easier.
"It has cemented TfL's reputation for being at the forefront of innovation and paved the way for the use of contactless payments on public transport not only in London, but across the world."
Previous limited-edition designs for Oyster cards were produced for events such as the opening of the Elizabeth line, the 2012 London Olympics and the late Queen's Diamond Jubilee.
In May 2022, E&T took an early look around one of the new Elizabeth line Tube stations at Farringdon.
