Full services of 140mph Japanese-built trains have begun operating between Kent and London.
The Class 395 Javelin trains run on sections of High Speed one (HS1) - the London to Folkestone Channel Tunnel rail link.
Southeastern said the service would cut journey times from Dover to London from more than two hours to 69 minutes. A preview service was introduced in June.
Passengers who use the Javelin commuter trains will have to pay higher fares.
A peak-time Ashford-London return will cost £48.70, compared with the usual fare of £40.60.
London-Folkestone will be £52.50 rather than £44.40.
'Fastest in country'
The preview service began running in June from Ashford to London St Pancras and was extended to Dover in October.
The full service will be officially launched by Transport Secretary Lord Adonis and double Olympic gold medallist Dame Kelly Holmes on Monday, when they travel on one of the trains from St Pancras in London to Rochester, Kent and back.
Dame Kelly will also have a train named after her.
The others are being named after athletes Steve Backley, Sir Steve Redgrave, Rebecca Adlington, Chris Hoy, Ben Ainslie, Daley Thompson, Duncan Goodhew, Katherine Grainger, Lord Coe, Tanni Grey-Thompson and Jamie Staff.
Southeastern managing director Charles Horton said the new train service was the fastest in the country.