Eurostar has released 75,200 promotional fares to and from London for £39.
The single rates apply to travel between January 3 and March 16 next year and must be booked by midnight on. November 27.
The standard class tariff applies to travel London St Pancras to Paris, Brussels, Lille, Rotterdam and Amsterdam.
A total of 18 destinations across an extended European network connected to Eurostar Channel Tunnel routes are included.
Promotional tickets on services between France, Belgium, the Netherlands and Germany are priced at between €16 and €35, depending on route.
For example, travellers have the option to visit Germany via connections in Brussels to destinations such as Cologne, Dusseldorf and Dortmund.
A new website, app, loyalty scheme and branding were unveiled last month as part of the creation of a new company, bringing together Eurostar and the Thalys European high speed rail network, with an ambition to carry 30 million passengers a year by 2030.
Flagged in January, the new-look Channel Tunnel high speed rail service carries a star logo.