Eurostar is to allow all passengers to change their tickets up to 14 days before departure with no additional fees.
Its new flexible fares, on sale from today, start at £39 each way.
The new policy will apply to all bookings made up to December 31.
The train operator announced today that its direct trains from London to Amsterdam and Rotterdam will start on July 9.
Initially, there will just be one train a day from London.
The return journey continues to be a connecting service through Brussels.
Trains to Disneyland Paris will start on August 2. The theme park reopens on July 15.
