It said that the loss was due to staff shortages, as well as an increase in costs.
However, the loss narrowed from the year-ago figure of £787m due to growth in traffic to 26.1 million from 3.9 million.
Revenue in the six months ended 30 June 2022 stood at £1.28bn, a 268% surge from £348m in the prior year.
Heathrow also highlighted the shortage of ground handling staff, which is said to have constrained its capacity.
According to the airport, the situation has improved after it restricted daily passenger numbers to 100,000.
This cap is expected to be in effect until airlines raise the number of ground handlers.
The airport also said that it is still loss-making and does not expect to offer dividends for the rest of this year.
Britain’s busiest airport said that the ground handling staff fell sharply over the last two years, as most airline companies cut costs during the pandemic.
Heathrow added that the passenger numbers, revenues and operating costs are in line with its H7 business plan that was submitted to CAA.
Despite the staff crunch, Heathrow said that the summer getaway had started well and everyone at the airport is working hard to get passengers on their journeys.
In order to achieve this, Heathrow said that it started planning nine months ago and started ramping up its own operations from November last year while encouraging the airline companies and their ground handlers to do the same.
Heathrow CEO John Holland-Kaye said: “The summer getaway has started well at Heathrow, thanks to early planning and keeping demand in line with airline ground handler capacity.
“I’m proud of the hard work everyone at Heathrow is doing which has helped millions of people get away already and will help millions more travel on their well-earned summer breaks in the weeks ahead.
“We can’t ignore that Covid has left the aviation sector deeply scarred, and the next few years will need investment to rebuild capacity, with a focus on safety, consumer service, resilience and efficiency.”
Earlier this month, Heathrow set a cap on daily passenger count to facilitate summer travel amid the recovery in air travel demand.