Heathrow is set to handle a record number of passengers today as competitors arrive for the Olympics.
The west London airport expects to handle 236,955 passengers - breaking the previous record of 233,562 set on July 31 last year.
Heathrow operator BAA said immigration waiting times have been within the targets set by the Home Office since new resources were put in place yesterday.
BAA added that additional staff are on duty in the baggage hall to quickly reunite Olympic teams with their baggage and equipment.
Athletes travel with around twice the number of bags as regular passengers - an average of nearly three items per athlete.
The busiest day for arriving athletes is expected to be July 24, when 1,262 athletes and coaches and 3,008 other Olympics-related arrivals are predicted.
More than 500 Heathrow and Locog volunteers, speaking more than 20 languages between them, welcomed groups of Olympic athletes and officials from their planes today.
London 2012 accreditation desks were operational in each terminal, allowing Games family members to collect their accreditation for the Olympic Village as soon as they arrive.
London 2012 coaches operated from airport forecourts for the first time today to transport athletes to the Olympic Village.
Nick Cole, head of Olympic and Paralympic planning at BAA, said: "Today heralds the start of Britain's biggest peacetime transport challenge and Heathrow's busiest ever period.
"The Olympic and Paralympic Games are a marathon, not a sprint, for Heathrow.
"The airport has some major challenges ahead, including unprecedented numbers of departing Olympics passengers and bags on August 13 and Paralympic arrivals and departures in August and September."