LHR still confusing

They close boarding on flights, so yes, you need to be at the gate early. My guess is that boarding starts at 9:50. What does your airline app say? The departure time may have changed to 9:50, so check with the airline.

For transiting LHR - something I avoid if at all possible - I prefer a minimum of 3 hours. I typically only fly to LHR if London is my destination.

LHR is more than confusing - it's a national disgrace for information.They've thrown billions at infrastructure but the information is poor before you get there, the "free travel area" map is for "groundside" where anyone can be.

How you transfer between terminals depends on whether you and your bags are checked through on the second flight. If so it's up to the airline to ensure that the conenction is viable when they sell the ticket, on arrival you follow the purple signs and don't need ETA. If the incoming flight is late and you miss the connection the airline will sort everything out. What to do is on this page https://www.heathrow.com/heathrow-blog/a-guide-to-connections some say that you also need the second boarding card but perhaps not...!

However, there is always Youtube! This is what you need for a real T3 to T5 connection https://www.youtube.com/watch?v=JsacJBmYFbo and it shows that you CAN collect the second boarding card during an airside transfer.

If you have two tickets seperate tickets for two flights you are in the other category, you need to add the published checkin time allowance for the second flight, an allowance to collect bags and clear immigration from the first plus 30 minutes or so for the actual transfer - this will be at least 3 hours. From T3 follow the large blue signs to the railway station, get a free travel ticket from the machine by the access gates and then get on the first train to T5 (Express or Elizabeth line) but bear in mind that the first train into the platform might be for T4 so listen to the announcements

We are elderly and can’t walk fast and if we truly have to make the connection in 1 hour 45 minutes then we can’t afford mistakes.

Hopefully you will check a bag so you don't have to deal with luggage. But I would also contact your airline and request assistance getting to Terminal 5. They should be able to help you.

Yes, you do not need an ETA for transiting in London.

You could request
Heathrow Airport Assistance.

Hopefully your seats on the flight from Philadelphia to London are in the forward section of the plane so you are off the plane quickly.

If the Heathrow website says 0950 departure, it means departure time. You need to check with your airline. We had that last week with someone on the forum, where notification from the airline followed well after it appearing on Heathrow information - in that case it had been rescheduled later, not earlier.

Contacting the airline for assistance between gates is a great suggestion. I really don't find LHR to be the nightmare that others do and I want to encourage you not to stress too much about this. You can do this and do it successfully. Any significant transfer at LHR requires walking and lots of it. Getting assistance will really help you on this front.

My experience is that the biggest time waster at Heathrow can be going through security. People aren't prepared and no longer have their bags and belongings ready to go. If you forget to take out liquids, electronics, or have water in your bottle from a previous flight, you will spend significant time in secondary screening. Be prepared and it will save you time.

I did this transfer last month. I'm through Heathrow quite a few times a year.

If this is on one ticket, and you have the boarding pass for the second flight, you just follow the Flight Connections signs (purple signs) to get the bus to transfer you from Terminal 3 to Terminal 5. (It might be a good idea to request assistance to help transfer you from gate to gate.)

When you arrive at T5, you will need to scan your boarding pass to enter the security area. You will have to go through security at T5. After security, you just go to the gate.

If you will share the flight number of your flight from London to Istanbul and the date, we can check to see the departure time.

If this is not on one ticket (you bought the tickets separately or from a third party), please let us know as the procedure is different.

Hi! All the info here is spot on and excellent! One running theme I am hearing - and want to second - is the advice to GET ASSISTANCE.

My mother and aunt live together, and travel frequently, and although neither of them technically need a wheelchair or a golf cart/driver/escort thingie, when they are making tricky, short connections they always request assistance and it has saved their bacon on numerous occasions.

So do not hesitate to ask! You deserve it!

Minimum connection time for flights on one ticket between T3 and T5 is 90 minutes, so will still be valid even if the second flight has been moved forward. It doesn't sound like it but should you have booked two separate flights then the time you have is not enough no matter which time for the second flight is right.

Frank II, we purchased tickets (there’s three of us) through American Airlines. The flight from London to Istanbul is operated by British Airways. The flight number is AA6613. We leave London September 24,2025
I checked both American and British Airways and the both show 10:35 departure.

As of today, your flight is BA 676 departing at 10:35.

Frank, I think what is confusing the OP is that Heathrow Airport Connecting Flights is showing AA6613/BA676 as departing 9:50am even though both AA and BA still show 10:35am departure.

I just ran this through Google (I was curious) and here is some info I'm finding:

Here's a possible explanation for why Heathrow's connecting flights information might show an earlier departure time (9:50am) for AA6613/BA676 on September 24, 2025, than what American Airlines or British Airways indicate (10:35am):

1. Difference in Reported Times:
   Airlines vs. Airports: Airlines typically report the scheduled departure time, which is the planned time for the aircraft to push back from the gate. Heathrow's Connecting Flight Information: Heathrow's system might be displaying an earlier time like "off blocks" or "estimated gate departure," according to FlightView. This represents the actual time the aircraft began moving away from the gate.

2. Padding in Airline Schedules:
   Airlines often "pad" their schedules to account for potential delays like taxiing, air traffic control, or gate congestion. This means the scheduled departure time (10:35 am) is longer than the actual expected flying time. So Heathrow's information could be reflecting the expected actual departure time based on factors like historical data and current airport conditions. This could be the 9:50 am time you are seeing.

In essence, Heathrow's connecting flight information might be attempting to give a more accurate representation of when the aircraft is likely to leave the gate, while the airline's scheduled time is a buffer to account for potential delays.

Regardless, always rely on the airline's information. It's always best to rely on the most up-to-date information directly from American Airlines or British Airways regarding your scheduled departure time, as it is the official time for your ticket.

I am so grateful for all of you who have taken the time to get to the nitty Gritty of this with me. I am hoping to talk to a person at American especially in arranging assistance. Our flight plan involves 2 domestic legs plus this Philadelphia to London and on to Istanbul and there are three of us needing assistance. Again thank you.