Travellers returning to the UK from "red list" countries will be sent to quarantine hotels for 10 days, Boris Johnson has announced.
People will also be required to fill in a form explaining why their trip is necessary, with enforcement of the ban on leisure travel stepped up at airports.
The Prime Minister told the Commons that passengers will be "met at the airport and transported directly into quarantine".
The Home Office said the rules will apply to people arriving from countries where non-UK residents are already banned from entering the UK.
These 30 destinations cover all of South America, southern Africa and Portugal.
Passengers will be "met at the airport and transported directly into quarantine", Mr Johnson explained.
The cost of staying in one of these hotels has not been disclosed, but further details will be released next weel.
Setting out more details of the measures, Home Secretary Priti Patel said: "Despite the stay-at-home regulations we are still seeing people not complying with these rules.
"The rules are clear, people should be staying at home unless they have a valid reason to leave.
"Going on holiday is not a valid reason, so we will introduce a new requirement so that people wishing to travel must first make a declaration as to why they need to travel.
"This reason for travel will be checked by carriers prior to departure."
Travel operators are expected to face fines if they fail to inspect these forms.
Ms Patel went on to give examples of people who "should simply not be travelling".
She said: "At St Pancras people have been turning up with their skis, that is clearly not acceptable.
"We see plenty of influencers on social media showing off about which parts of the world that they are in, mainly in sunny parts of the world.
"Going on holiday is not an exemption and it's important that people stay at home."
Labour chair of the Home Affairs Committee Yvette Cooper said the measures "don't go far enough to deliver a comprehensive system".
Airline bosses are demanding that the Government provides an "urgent road map for the reopening of air travel".
The chief executives of British Airways, easyJet and Virgin Atlantic were among those calling for the Government to publish a plan that "draws upon the tools available now to us, including testing, working in concert with vaccine rollout at home and internationally".
They added: "The time has now come for a bespoke support package that can get UK airlines through this crisis."
Paul Charles, chief executive of travel consultancy The PC Agency, said: "Many questions remain about the damage these extra quarantine measures will do to the economy and the travel sector.
"What is the economic impact in terms of lost jobs and likely business failures, and what is the exit plan for ending these restrictive measures?
"It would be much more effective for the Government to put more resources into enforcing quarantine at home. Tougher fines for those not complying and daily physical checks by police, alongside the need to test negative before entry to the UK, would prevent infection spreading."
– These are the countries affected by the quarantine hotels policy:
Democratic Republic of Congo
Portugal (including Madeira and the Azores)