Oman and Qatar have been added to the “red list” of countries from where travel to England is banned, the UK’s Department for Transport said on Monday.
Ethiopia and Somalia have also been added to the travel ban list.
It means travellers coming from these countries have to quarantine in a hotel at a cost of £1,750 ($2,419).
Hotel quarantine applies to anyone who has been in a red list country in the previous 10 days, even if only transiting at an airport.
Travellers who fail to quarantine in a hotel despite being in a red list country could be fined up to £10,000.
Meanwhile, Portugal and Mauritius have been removed from the list, meaning those travellers only have to quarantine at home for 10 days.
The changes come into force at 4am (GMT) on Friday.
The government said the ban on commercial and private planes travelling from Oman, Ethiopia and Qatar will also come into force on Friday to reduce the risk of importing “variants of concern”.
The changes to the red list are the first since Britain introduced its hotel quarantine system.
The red list - which includes the UAE, southern Africa and all of South America - is to “protect the country against new variants of Covid-19”.
The department said the changes come at a “critical time” for the vaccination programme.
“The government has made it consistently clear it will take decisive action if necessary to contain the virus and has taken the decision to add these destinations to the red list,” it said.
The government said it decided to axe its ban on direct flights and sailings from Portugal due to “evidence that shows the risk of importing a variant of concern from these destinations has reduced”.
“Portugal has put steps in place to mitigate the risk from its links with countries where variants have become a concern, and now has genomic surveillance in place,” the government said.
Under the current rules, foreign travel from the UK is banned apart from for exceptional reasons.
Foreign leisure travel could be permitted for people from England from May 17 under Boris Johnson’s plan for easing lockdown restrictions.
UK 'red list' travel ban countries:
Entry to the UK is banned from the following countries for non-citizens.
British and Irish citizens, and those who have residence rights in the UK, are able to enter from these countries but must quarantine in a government-approved hotel for 10 days.
Angola
Argentina
Bolivia
Botswana
Brazil
Burundi
Cape Verde
Chile
Colombia
Democratic Republic of the Congo
Ecuador
Eswatini
Ethiopia
French Guiana
Guyana
Lesotho
Malawi
Mozambique
Namibia
Oman
Panama
Paraguay
Peru
Qatar
Rwanda
Seychelles
Somalia
South Africa
Suriname
Tanzania
United Arab Emirates
Uruguay
Venezuela
Zambia
Zimbabwe
Guests leave hotel quarantine 'prison' at London Heathrow - in pictures:
