The holiday giant had planned to resume its international services on 24 June but changed the date after Transport Secretary Grant Shapps revealed Portugal would be taken off the green list and moved to the amber list from next Tuesday (8 June).
No countries were added to the green list in the update, while several other destinations, including Sri Lanka and Egypt, were added to the red list.
It comes as Easyjet said it would “review” its flights to Portugal following the amber list decision.
The announcement sent British holidaymakers into a panic, with some wondering whether they would be given refunds for holidays booked in June.
So, what has Jet2 said about the travel changes - and what is its cancellation policy?
Here is everything you need to know.
What is Jet2’s cancellation policy?
Jet2 had originally suspended its services up to 24 June when the initial green list was announced.
But, after the latest travel changes, all flights this month have been cancelled.
And flights to Turkey - on the red list of the government’s travel traffic light system - will not start up until 22 July as restrictions on the country look unlikely to be lifted.
Those affected by the government’s announcement need not worry, as Jet2 has set out its policy for anyone impacted by the changes.
The airline has promised that anyone affected by the update or who was preparing to travel before 1 July to an amber list country would be given the option of a full refund.
Alternatively, people will also be able to rebook their holiday if they wish.
Customers will also not be forced to accept refund credit notes, Jet2 said.
Furthermore, the holiday giant said it would allow customers who have booked a holiday to a current amber list destination and are due to fly between 1 July and 21 July to amend their booking at no extra cost.
Company boss Steve Heapy criticised the government’s handling of international travel restrictions following the changes.
He said: “We know how disappointed our customers will be and we share their concerns and frustrations.
“The government has repeatedly stated that it is making decisions based on infection and vaccination rates, yet many destinations continue to be left off the Green List despite having low infection rates and high vaccination rates.
“When you apply the government’s own criteria for making decisions about travel, we simply cannot understand why more destinations across Europe, the Mediterranean and the Canary Islands are not allowed to open to UK holidaymakers.”
Jet2 is calling for the government to show “complete openness and transparency” when it comes to the data to ensure customers can understand why the decisions have been made.
Which countries are on the amber list?
Prospective holiday makers were eagerly anticipating the “upgrade” of several amber countries to green but were left disappointed when no extra destinations were added to the quarantine-free list.
Those returning from amber countries must take two post-arrival tests.
They are also required to self-isolate at home for 10 days, although people in England can reduce that time if they take an additional negative test on day five.
But the government does not advise travel to the countries on the list.
As well as Portugal, including the Azores and Madeira, from 8 June, the most recent amber list includes the majority of Europe, as well as the US and Canada.
The full list of amber countries can be found on the UK Government’s website.