All UK travel corridors, which allow arrivals from some countries to avoid having to quarantine, have now closed, the BBC reports.
Travelers arriving in the UK, whether by boat, train or plane, also have to show proof of a negative Covid-19 test to be allowed entry.
The test must be taken in the 72 hours before travelling and anyone arriving without one faces a fine of up to £500.
All passengers will still be required to quarantine for up to 10 days.
The isolation period can be cut short with a negative test after five days.
The government has said the travel corridor closure will be in force until at least 15 February.
Under the new rules, travellers arriving from the Falklands, St Helena and Ascension Islands are exempt.
Those arriving from some Caribbean islands are exempt until 04.00 GMT on Thursday 21 January.
