Heathrow handled a record of almost 75 million passengers last year – a rise of 2.2% over 2014.
Chief executive, John Holland-Kaye, described 2015 as a “banner year” for the London hub.
December saw numbers pegged at 2014 levels with 5.9 million passengers using the airport during the festive season.
Emerging markets saw growth in the month including 16% up to Mexico, 6% to the Middle East and 5% to China.
Larger, quieter aircraft contributed to the increase in annual passenger numbers, with seats per aircraft increasing 2.1% to 209, load factors remaining constant at 76.5% and passengers per aircraft rising to 1.9% to 160.
At the end of 2015, more than 20 daily Airbus A380 superjumbo departures and arrivals were operated by eight airlines.
Holland-Kaye said: “2015 has been a banner year for Heathrow, serving more passengers than ever and being recognised in a number of awards as the best major airport in Europe for both passenger service and eco-innovation.
“The record levels of passenger satisfaction are due to a significant increase in training, apprenticeships and the number of front line colleagues moving into management roles.
“Our new expansion plan will make Heathrow the most sustainable hub airport, and Britain the best connected country in the world. We are ready to serve.”