Eurostar seats starting at £39 are available for one-way travel in a week-long sale starting today (Wednesday).
The promotion covers summer travel between May 4 and August 24 with 68,000 tickets available.
The offer covers travel from London to Paris, Brussels, Lille or Rotterdam.
The high speed Channel Tunnel rail passenger operator believes a rise in interest in festivals around Europe after the pandemic put them on hold throughout 2020 and most of 2021 will help drive demand.
All tickets are flexible, with no exchange fee up to seven days before departure.
But blackout dates include May 7, 8, 25, 26, 27, 28, 29; June 2, 3, 4, 5, 6, July 14, 18, 21, 22, 23, 24; and August 1.