The traditional paper train ticket is being phased out across the UK, the Rail Delivery Group (RDG) has said.
All major stations and every train operator now has the option to use smart tickets, with nine in 10 journeys "soon" available in this format, RDG, which represents rail firms, said.
Smart tickets can be bought online and stored on smartphones or smartcards.
Consumer group Which? said the plans were a "positive step" but "long overdue".
The process has required a rollout of new technology across the network, with recent upgrades at Waterloo, Edinburgh Waverley and Gatwick Airport stations.
This will be followed by new readers and computer software at Blackfriars, Watford Junction, City Thameslink, London Bridge, East Croydon and Shenfield.