How much time needed at Heathrow

These questions can be a challenge to answer, primarily because no one can accurately predict the actual conditions at the airport on your departure date in advance. You may sail through or you may find yourselves in a crazy back up.

In general, 3 hours before an international flight is the suggested time. You will need to check in, check bags (if any) go through security and then wait for a gate assignment. Once you know your gate you move there. Most international flights actually start boarding about an hour before departure.

Here is the info directly from the Delta website:
"When you’re traveling outside of the United States, we make the suggestion to arrive at least 3 hours prior to your departure. You must be checked in at least 1 hour before your scheduled departure. Additionally, we recommend being at the gate and ready to board 45 minutes before your scheduled departure time."

There are quite a few restaurants and several lounges at Heathrow that might make it easier to wait.

3 hours minimum for travel to the US

Heathrow is vast - you’d want to err on the side of allowing more time, not less.

Heathrow is an airport that I always arrive 3 hours early.

I fly LAX to LHR yearly and vice versa. Speaking from experience: 3 hours at a minimum.

Two hours enough?

It might be. I suspect the majority of bookies would lay odds against success.

When to arrive

We recommend getting to the airport three hours before your flight if you're travelling internationally, or two hours if you're travelling domestically or to Europe. -- https://www.heathrow.com/departures/checking-in
The folks that run the airport recommend 3 hrs. I would give them credit that they know what they are doing

Three hours minimum. Heathrow is huge and spread out and you really don’t want to be sweating it. Some of the gates at terminal 5 require you to walk though a massive shopping mall first and then take a train to the gate.

Security took forever for me last May, but it was also around the reopening so it seemed like there were a lot of very infrequent fliers delaying things.

If you are there early and have time to kill, you’ll likely find that the airport prices aren’t outrageous.

After a year like last year definitely 3 hours. If you find yourself with extra time then you can

• Go to a lounge if you have access
• Get some breakfast or coffee. Every terminal seems to have a Pret or Costa and maybe some sit down dining options
• Find a quiet corner to sit and read, cull/edit pics, update a travel journal, catch-up on email.

Edit. Forgot to add shop if that’s of interest.

My experience last month.....

I checked in online, I only had carry on luggage, did not have to stop between arrival at the airport and heading towards security and had access to Fast Track security.

I arrived two hours prior to flight and had plenty of time.

The same was true in October but the security lines were long. I still made it in time.

However, for regular security give yourself extra time. Ditto if you have checked luggage.

Three hours to be safe. You always want to be on the side of being able to grab a coffee and relax rather than running to get through security.