Heathrow suffered a 72.7% drop in passenger numbers last year, the airport said.
Just 22.1 million people travelled through the west London airport in 2020, down 58.8 million on the previous 12 months.
The decline was caused by the impact of the coronavirus pandemic.
In December, passenger numbers fell by 82.9% year on year to 1.1 million, amid a new strain of Covid-19.
Heathrow chief executive John Holland-Kaye said: “The past year has been incredibly challenging for aviation.
“While we support tightening border controls temporarily by introducing pre-departure testing for international arrivals, as well as quarantine, this is not sustainable.
“The aviation industry is the cornerstone of the UK economy but is fighting for survival. We need a road map out of this lockdown, and a full waiver of business rates.
“This is an opportunity for the Government to show leadership in creating a common international standard for pre-departure testing that will allow travel and trade to restart safely so that we can start to deliver the Prime Minister’s vision of a global Britain.”
It was announced last week that all travellers to the UK from international destinations will have to test negative for coronavirus before they can enter the country.
Passengers arriving by boat, train or plane – including UK nationals – will have to take a test up to 72 hours before leaving the country of departure.
The new rules are expected to come into force later this week.