Transport Secretary Grant Shapps says face coverings will be mandatory on public transport in England from 15 June.
Shapps says you can be refused travel if you do not comply – and could face a fine.
But he says he expects the “vast majority” of people will adhere to the new rule.
Asked who will police the wearing of face masks, the transport secretary says it will be a “condition of travel”.
Grant Shapps adds the government has been in discussions with the unions about the policy and it is in “everyone’s interests” to see it work.