The new CT scanners mean passengers travelling through all four terminals at the UK's hub airport will no longer need to remove liquids or electronics from their hand luggage.
Heathrow said the upgrade would speed up transit through security, reduce stress for passengers and drastically cut plastic waste.
CT scanners provide better images of cabin baggage, allowing security to process more passengers – "thousands" – per hour. The airport also estimates the move will reduce plastic bag usage by almost 16 million a year.
Last year, more than 97% of passengers departing Heathrow cleared security in less than five minutes.
