UK residents returning from coronavirus hotspots abroad will have to quarantine in hotels from 15 February, the government has confirmed.
Hotel owners will be asked to provide rooms for more than 1,000 new people every day, documents suggest.
Passengers will have to stay in their rooms for 10 nights, with security guards accompanying if they go outside.
Labour called the measures "too little, too late" to deal properly with new overseas strains of Covid.
It is beyond comprehension that these measures won't even start until 15 February," said shadow home secretary Nick Thomas-Symonds.
Quarantine hotels are expected to be set up near airports including Heathrow, Gatwick, London City, Birmingham, Bristol, Manchester, Edinburgh, Glasgow and Aberdeen.
The rules will apply to UK nationals and residents returning to the country from 30 "red list" Covid-19 hotspots - including several South American and African countries where new Covid variants have been detected in large numbers of people - and passengers will be expected to pay for the cost of the accommodation.
Most foreign nationals from high-risk countries already face UK travel bans.