Overall crime on public transport in London has fallen by 4% in the past year, figures from Transport for London (TfL) have suggested.
There were 38,298 offences in 2010, or 105 per day, compared with 39,944 in 2009. Crime on buses dropped by 2.5% and on Tubes and the DLR by nearly 7%.
London's mayor, Boris Johnson, said there had been fewer crimes on transport than at any point since 2004.
But the Lib Dems said bus crime was going up in a third of boroughs.
Rises in areas including Barking, Southwark and Tower Hamlets meant the mayor should "take great care when boasting about crime statistics", said Caroline Pidgeon, the Lib Dem vice-chair of London Assembly's transport committee.
The number of recorded offences on buses fell year-on-year by 610, or 2.5%, to 24,283.
There were 13,640 crimes on the Tube and the Docklands Light Railway, a reduction of 977, or 6.7%, last year.
Offences on Tramlink fell from by 60 to 364, a 14% drop.
London Overground crimes rose by 28%, from 438 to 611, but this followed the expansion of the network to include the former East London Line.
"Inquisitive" patrols at stations played a part in the overall fall, British Transport Police said.
"We do not tolerate anti-social behaviour or any other behaviour that makes people feel unsafe while they travel," added Assistant Chief Constable Alan Pacey.
"Some 12,000 CCTV cameras across the Tube network are vital in helping us identify offenders and solve crime."
Mr Johnson said he was "encouraged" by the overall figures, but said: "We cannot be complacent."
But Labour's Val Shawcross, who chairs London Assembly's transport committee, said she was "deeply concerned about the impact of the mayor's plans to cut 1,000 police officers, which threatens the vital work of making London safer".