London's electronic Oyster travel card is to be made available to foreign visitors to boost inbound UK tourism.
Overseas tourists will be able to buy and receive the smartcard before they travel, after a deal was struck between Transport for London and VisitBritain.
Initially, the cards will go on sale in India, Hong Kong, Singapore, Spain, Portugal and the USA. The cards can be bought on VisitBritain's overseas websites from March 2007.
Users buy credit for the card - so it can be used in a "pay-as-you-go" style - and fares are also discounted.
London Mayor Ken Livingstone said: "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."
The British Hospitality Association (BHA) welcomed the move. Martin Couchman, deputy chief executive at the BHA, said: "Anything that makes life easier for tourists has to be good."
By Daniel Thomas