Passengers travelling internationally from Monday will need to carry a new form that sets out their trip is permitted under the stay-at-home restrictions, the government has announced.
The form must be downloaded, signed before travel and carried, or is downloaded onto a mobile phone.
Carriers will be checking the forms have been completed before boarding, either at check-in (online or at the check-in desk) or the departure gate.
Passengers who do not have a valid form may be denied access to their booked service.
Carriers will also be legally obliged to set out on their website that the form must be completed before travelling.
Police have been stepping up their presence at ports and airports in recent weeks to enforce ever evolving travel restrictions.
Officers will now be conducting spot checks and have the power to ask travellers to produce a completed form.
It will be an offence to fail to produce a completed form and individuals could face a £200 fine.
Stay-at-home rules are still in place, which means it is illegal to travel abroad without a permitted reason, such as for education or work, officials said.
The police will undertake spot checks at UK ports across the country to ensure passengers are complying with domestic lockdown rules.
Passengers who are identified by police as attempting to travel internationally for reasons that are not currently permitted will be asked to return home and risk receiving a fixed penalty notice for breaking stay-at-home rules.
These fines start at £200 and ladder up to a maximum of £6,400.
The Home Office announced an additional £60 million for police in February – including £2 million to cover the costs of extra activity by police at airports and ports – which brought the total amount of funding available to forces since the start of the pandemic to nearly £200 million.