London's electronic Oyster travel card is to be made available to foreign visitors to boost inbound UK tourism.
The cards can bought on VisitBritain's websites
Overseas tourists will be able to buy and receive the smartcard before they travel thanks to a partnership between Transport for London and VisitBritain.
Initially the cards will go on sale in India, Hong Kong, Singapore, Spain, Portugal and the USA.
Users buy credit for the card - so it can be used in a "pay-as-you-go" style - and fares are also discounted.
It can also register weekly and monthly travel cards.
The cards can be bought on VisitBritain's overseas websites by March 2007.
London Mayor Ken Livingstone said: "Oyster is already a proven success with Londoners and this new deal will make it easier for millions of overseas visitors to get around London.
"The best way for visitors to travel around the capital is usually by public transport so this deal will provide simpler, cheaper and quicker journeys."
Kenny Boyle, VisitBritain's director of commercial and marketing services, said: "With more than 12 million visits to our overseas websites every year, TfL and other commercial organisations recognise VisitBritain can help them reach new customers.
"The Oyster card is the smartest, quickest and cheapest way around London and it's fantastic we can now offer even greater value for money to international visitors."