Long queues have formed at bus stations as commuters avoid the London Underground.
TfL said a record 7,961 buses were being used today.
Commuters faced long queues at Harrow-on-the-Hill station on the Metropolitan line today as the first morning of a 48-hour Tube strike got underway.
Transport for London said its ambassadors will help keep Tube stations open and passengers on the move during the 48-hour walkout by London Underground workers.
TfL said a record 7,961 buses were running in London after 266 were added to the service.
Tube strike: Licensed & trained TfL Ambassadors will help keep Tube stations open & provide travel info & advice to customers.
Passengers have reported busy scenes on the Victoria line as rush-hour commuters were warned to expect severe disruption.
Transport for London is operating services between Seven Sisters and Brixton on the line approximately every eight minutes.
If you, or someone in your family, commutes to London - long delays are expected over the next two days because of another tube strike. The 48-hour walk-out by staff will start at nine o'clock tonight.
The industrial action is over plans to close ticket offices with the loss of a thousand jobs. So what will the impact be on travellers from the South? Here's David Wood.
For more information on how your journey to and from London may be affected you can visit the Transport for London website.
For live status alerts on social media you can follow: @TfLTRavelAlerts
London Overground services will be unaffected by strike action but trains and platforms are expected to be far busier than usual, TfL has said.
Strike update- London Overground services are not expected to be affected by industrial action, but will be much busier than usual.