Suggested arrival, check-in for international flight out of LHR

Why would you want to add this stress on the morning you fly home? So many variables. Why not drop the car off the night before and stay in London or an airport hotel, there are two attached to terminals, the night before your international flight? You probably need to be at the airport at 8 AM for an 11 AM flight depending on your carrier's requirements.

You can never be certain of the traffic conditions getting to Heathrow, we learned that the hard way. The stress of that was just too much and never want to go through that again. Also, dropping off the car can be a nightmare at that time of the day and take more time than you can ever imagine, that too has happened to us. Now, if we have a flight before noon, we stay at a hotel at Heathrow, allowing for a stressless morning and a relaxed breakfast before departure.

Dear Deb, you don't say where you are flying to, which greatly affects how early you need to get to the airport. Your airline should be telling you the minimum check-in time (and which terminal). Typical figures are minimum 40 minutes for a European flight, 2 hours+ for an intercontinental flight.
10:50 - 1-2 hour check in, - 1 hour contingency, - 1 hour to drop off car, do paperwork, and get to terminal = arrive Heathrow 07:50/06:50, right in the middle of the rush hour.
Where in South Wales? Cardiff may be 2½ hours to Heathrow, other places could be 3-4. Plus any potential traffic delays. = leave 04:50/02:50 latest. Do you really want to do this?
I would say drop off car, get a train to London and stay in a hotel within walking distance of Paddington station. You would still need to leave the hotel ~07:00. Or drop off at the airport the night before and stay in a boring airport hotel.

I lived in the UK for five years outside of London and experience taught me that road conditions on way to LHR can be slow to temporarily non-moving in the case of an accident or roadworks. Turn in the car the day before.

I suggest being at the terminal three hours prior to your flight. Heathrow can be very unpredictable and I have spent two hours just getting checked in and through security there. No way do you want to drive in the day of. We missed the signage for rental car return and ended up driving a very long way on the freeway in crazy traffic before we could even turn around. You would think returning a car at an airport would be the easiest thing in the world but somehow we flubbed it. Luckily we were not flying out that day, that was before ending our trip with five days in London. A lot can go wrong in attempting this, I strongly suggest staying in London or at the airport the night before.

Well, thanks for the insight, friendly and helpful folks. I was trying to avoid an overnight stay at an airport hotel. Sure don't need any hiccups at Heathrow. We are flying to Croatia to pick up a tour on the Adriatic.
Regards,
Deb

Sorry, but it's madness to drive from Wales to Heathrow for an 11 am flight. Way too stressful and it's likely to be a 3-4 hour drive at that time of day, not 2 hours.

Why drive all the way to London to fly to Croatia? Look at flights from Cardiff or Bristol instead.

Yup, fly from Bristol to Dubrovnik or Zadar. Have you already booked your LHR tickets?

Yes flights to Zagreb already booked.

Thanks
df

I've had a few early morning flights out of LHR and always stayed at the Sofitel which is attached to Terminal 5. (The flights were on BA.)

By staying at the airport rather than the night before at a London hotel allows me to sleep a little longer. An since I'm a night owl, the extra 30-45 minutes helps.

I also suggest taking the advice given by many of the previous posters and do not try to drive in on the morning of your flight. Drive in the night before, get a good night sleep and you'll be ready to hit the ground running in Croatia.

Wow, what a trip!! Have fun!

Do not attempt to drive from South Wales into LHR to catch a flight that early in the morning. Drop the car off the night before and get an airport hotel as others have suggested. There are too many things that could go wrong. It will take you far more than two hours to get from South Wales to LHR. Traffic going into London in the morning can be at a standstill. You need to be walking into the terminal by 7:50 am. There is likely to be long lines at the check-in desk (unless you have priority) and getting through security will also take time. Walking to the gate can take 20+ minutes at Heathrow. I fly in and out of Heathrow every year and I am always anxious about catching a morning flight. In fact I prefer to book a midday or afternoon flight for the very reason it is hard to drive into London early in the morning.