Heathrow said 7.7 million passengers travelled through the airport in July, demonstrating the resurgence in foreign travel.
That is up 22% on the total of 6.3 million during the same month last year and is just 1% below the figure of 7.8 million recorded in July 2019 before the coronavirus pandemic.
The year-on-year surge in passenger numbers last month was driven by fights to and from Asia (up 129%) and North America (up 77%).
Travel to those regions was limited a year earlier, partly because their pandemic restrictions lasted longer than in some other parts of the world.
July was Heathrow Airport's busiest ever month for flights to Turkey, with more than 73,000 people flying to the country.
It also saw near-record levels of departures to Portugal, Italy and Gibraltar.
The west London airport reported a "strong start to the summer season for passenger service," with security queues "consistently under five minutes."
Chief executive John Holland-Kaye said: "It's great to see so many passengers getting away to grab some summer sun. We've got a great range of popular destinations and our teams are delivering excellent service which will ensure your travels get off to the best start."
