Some 856,000 fans, including crowds for football and a “conservative” estimate of 500,000 for the men’s cycling road race, watched on Saturday, with a further 900,000 turning out on Sunday, LOCOG said.
A further 370,000 spectators took in the action on Monday when no football matches took place.
Attendee rates for the three days were 86 percent, 92 percent and 88 percent respectively.
The London organisers have been dogged by questions about empty seats at several venues despite overwhelming pre-Games demand from the British public.
LOCOG insist the problem lies with unoccupied accredited seating which is reserved for officials.
Around 3,800 tickets were retrieved from international sports federations and put on sale to the public on Monday, LOCOG said.