London to Aix-en-Provence trains will begin running every Saturday in May and June, stopping in Lyon and Avignon.
Prices are €99 in standard class Lyon-London and €199 in premier, rising to €109 standard and €249 premier for Aix-London.
The first train leaves St Pancras on May 4 at 7h17 and arrives 4h43 later in Lyon Part-Dieu, 5h52 later in Avignon and 6h17 later in Aix at 14h34.
However, travellers heading from France to London will face longer journey times due to customs checks needing to be made at Lille. On the London outbound services these checks are done before boarding at St-Pancras.
Trains leave Aix at 15h57, Avignon at 16h21 and Lyon at 17h38 to arrive in London at 22h39. The Aix-London journey takes seven hours 42 minutes.