Travellers trying to return from France on Friday to avoid the quarantine restrictions face paying hundreds of pounds.
The cheapest ticket on a Eurostar train from Paris to London is £210, compared with £165 on Saturday.
The cost of taking a car through the Channel Tunnel on Eurotunnel Le Shuttle services on Friday morning is £260.
All trains after midday are fully booked.
P&O Ferries has limited availability, but one person travelling with a car from Calais to Dover can buy a ticket for £200.
Travellers in the south of France face a struggle getting back to the UK before the 4am Saturday quarantine deadline.
Many direct flights to the UK on Friday are sold out.
Flight booking website Skyscanner suggested there were no direct flights from Biarritz to London.
The cheapest option it offered was to take one flight to Paris, another to Belfast and a third arriving at London Stansted shortly before midnight, at a total cost of £284.
The lowest priced ticket involving just two flights is £579 with Air France, changing in Paris.
Whichever mode of transport travellers use, they will need to move quickly as many services will be fully booked by Friday afternoon.