Connecting flight (not a through ticket)

We have often done separate tickets on British Airways because I like to book our long-haul flights between SEA and LHR in business class with miles, then book the short flights from LHR to our next destination ( Spain, Germany, Switzerland, etc.) and back as a separate round-trip in Economy. On the way over, I am comfortable with a 4-hour spread between our arrival at LHR and the departing flight to the Continent. The first time we did this we had to transfer from T5 to T3 and I timed it: 45 minutes gate to gate, but we were almost the first off the plane. Of course you still have the uncertainty of an on-time arrival into Heathrow, but the 4 hour gap should cover most delays.

For the flight back, however, I am not comfortable with a same-day flight to LHR to catch our long-haul flight home, so I always build in an overnight. We use this as an opportunity to spend the night somewhere outside of London---so far have stayed in Windsor and in Henley-on-Thames. I feel we made good use of the opportunity to explore these new and interesting places in a leisurely way. And it definitely avoids the stress of worrying about missing that long and expensive flight home.

Having gone through Heathrow many times en route to other destinations you should be fine so long as you do online check-in Rome for your onward flight. On the Heathrow website both flights are shown as arriving and departing from Terminal 5, so you will not be leaving the airside of security nor clearing immigration; you just go to departing gate. Even if it is necessary to change terminals should not be a problem as Heathrow, I have found, makes it pretty easy with busses between the widely separated terminals.

Thanks so much.. I'm beginning to agree Lola- Windsor sounds perfect. If we rebook, our new flight won't leave until 2:10 the following day. Should we go to Windsor but then stay close to Heathrow, or do we have time to actually stay in Windsor and get the feel of the cute little town and go to a pub for dinner and take an Uber back the next day?

If so, what hotels do you like in Windsor?

You could consider staying at an airport hotel and just going to Windsor for the day. I recently stayed at the Sofitel hotel at Heathrow terminal 5 and it was marvelous to have a leisurely morning and be able to walk to the terminal - it definitely reduces the stress on the day of departure for me.

If it were me, I would change it to allow a day between the Rome flight and your transatlantic flight, I'm a bit jaded because I was scheduled to fly on BA from Bilbao to London on the day that they had their systemwide IT failure. I ended up buying a ticket on Vueling on my own dime after spending 8 hours in the Bilbao airport (with almost no helpful info from BA ... customer service was almost non-existent. Had it not been for the pilot coming out and sharing what he knew, all of my info would have been from news reports and twitter). I have filed for a refund of my BA ticket and EU 261 compensation; however, the whole event (and the days of travel disruption stories on the news) reminded me why it is never a good idea to buy separate tickets on the same date.

If everything goes well, 4 hours is plenty. If something unusual happens, be prepared to exercise the backup plan.

We make plans similar to Lola's, whether it's LHR or CDG. Last year we landed, went through immigration, retrieved our checked bags and transferred to T2, checked our in for our next flight and went through security in a bit over an hour. The closer you are to the doors of the plane, the less time it will take. We also add a day on the end before our international flight and kind of use it as a transition day. I don't want to end a vacation stressing about making a flight home.

I really appreciate all your help. We are changing our plans. Now we just need to decide if we want to stay in Windsor for the night, or come back to the Sofitel or similar hotel to be ready to go the next day.
If anyone has a hotel they like in Windsor, or info regarding where to stay when visiting Windsor please do let me know. You have been so helpful, and I'm feeling more relaxed already!

Hi Jen---if your flight home does not leave til 2 in the afternoon, I would suggest you stay in Windsor, to take advantage of the evening and morning there, instead of an airport hotel. You can stroll the Thames path in the evening, see the changing of the guard at the castle in the morning, maybe wander over to Eton to see the future leaders of the UK in their tailcoats, have a nice dinner in a pub by the river or a nice Italian restaurant ( which we did). There is more to do which we did not have time for---but will try to include next time. I want to wander the Windsor Castle grounds, ala Bill Bryson.

We stayed at a wonderful Band B ( Frances Lodge) which unfortunately is not in business any more. It was around £90 for a lovely "design" room. I hope you can find something suitable. Some of the hotels are really pricy---they seem to be "destination" spots for wedding and parties, but if you are there mid-week that may not apply.

We took the bus to and from Windsor and it we slow (45 minutes) but inexpensive (£6 or so). Apparently taxis from Heathrow to Windsor are London taxis and really expensive, but from Windsor to LHR you can get a Winssor taxi which is reasonable. At least that is what I have read. Did not try that out personally. But I am sure others here can advise you.