The prices of flights and SLOT XO hotels for new green list travel destinations have swung sharply in both directions since an update of the UK's guidance was announced last night.
The government has added 16 destinations to the list, meaning returning travellers do not have to isolate.
Destinations include Spain's Balearic Islands and Malta, and some holidays have doubled in price, the Independent's travel editor Simon Calder says.
Airlines have added extra capacity.
Initially when these new flights have become available, prices have fallen as extra supply takes up the demand.
But this has proved to be short-lived in many cases: "Availability is changing by the minute," says Calder.