In his first policy act as new mayor of London, Sadiq Khan is introducing a one-hour "hopper-fare" for bus users as promised in his election manifesto.
The fare system allows bus passengers to make an extra journey within an hour of touching in when using an Oyster card or contactless payment.
Previously, customers were obliged to pay £1.50 each time they boarded a bus.
The hopper-fare will "help ensure everyone will be able to afford to travel around the city," Mr Khan said.
It is scheduled to be introduced in September.
"The cost of a fare in London has risen for eight years in a row and now that I'm mayor I am determined to prevent the cost of travel from becoming a barrier to work."
Transport for London said it did not have the technology to allow passengers to enjoy unlimited bus transfers within one hour but it was hoping to upgrade its ticketing technology in 2017 and possibly introduce unlimited timed fares by the end of 2018.
A single journey costs £1.50. London buses stopped accepting cash payments for fares in 2014 and it is only possible to buy a single ticket - or use a travelcard which covers multiple journeys in the same day.
"It's Mayor Sadiq Khan's first big transport policy announcement and perhaps there is little surprise - that from the son of a bus driver - it involves buses.
From September, bus passengers who use Oyster and contactless will be able to change buses within one hour and only pay one fare.
Bus passengers - unlike tube passengers - at the moment have to pay every time they use a bus. With tube passengers the fare is decided by the zones. Many have said that is unfair.
The idea of a one hour "hopper" has been around for some time, it was part of the Liberal Democrats Mayoral manifesto in 2012 and Transport for London (Tfl) previously said a one-hour bus ticket will cost £50m a year.
There is also a statement of intent here from Tfl who have a new boss to impress and that is - it will deliver whatever the mayor wants. "
Sadiq Khan: A new broom for South Asian politics in London?