Heathrow - plane to train midweek midday - how long?

There are no trains from Heathrow to Bath - you will need to go to either London Paddington station by Heathrow Connect or Heathrow Express and connect to your Bath Spa train there, or take the Railair bus to Reading (pronounced redding) station and connect onto a train to Bath Spa there.

All sorts of things could delay your joining your booked train - your plane could be late, your companions' plane could be late, either or both of you may be delayed at baggage claim, either or both of you could be delayed at Border Control (what dinosaurs like me used to call Immigration), you have to meet up and do what people do when they meet up, and you then have to find the bus or train to your connection and pay for them, and the bus could be held up in traffic or yet another Heathrow Express strike might affect that. Then you need to negotiate either Paddington or Reading.

Or deal with the National Express coach - but you asked train.

If you have Advance tickets and miss the train they are worthless and need to buy new tickets.

If you are going to meet up and use the Railair coach, don't bother coming together at one of the terminals - meet up at the central bus station which is roughly in between terminals 2 &3. This will save you about 15 minutes.

Depending how many of you there are as you don't specify, you might benefit from such things as group save tickets which although not as cheap as using the lowest fare advances is a saving over the single person's fare.

Thank you Marco and Nigel. It sounds like an advance ticket would be risky. I was considering it and the train because I read that the buses might be sold out. I guess I'd better wait until we(2) are there.

Why not plan on staying the night, before heading to Bath? You could stay in Windsor (a 15 min. taxi ride or a 45 min. bus ride from the airport), then catch the train from there the next morning (you'd have to take the train from Windsor to Slough, change there for Redding/Bath if I remember correctly). That way you could get advance fare ticket and save a bundle! Or you could stay at one of the hotels near Heathrow, or take the bus to Redding and stay there. Personally, I'd stay in Windsor- it is a lovely little town and you'd have time to see a good bit of it as well as the castle, have a nice dinner, etc..........

Thank you. I will check out Windsor as an option.

The buses would rarely sell out, but you have the same issue should you miss them - you will have to pay any fare difference plus an Admin fee to be carried in the next service - space permitting.

With so many variables, I agree that it's risky to buy an advance-discount train ticket for shortly after your planned flight arrival. An Off-Peak ticket from London Paddington station to Bath, purchased on the day, costs 31.50 pounds per person in standard class (shown as $55 on our maps). Trains run frequently.

If purchased before August 28 (5 p.m. ET), all full-fledged BritRail passes and BritRail England passes come with one extra travel day for no extra charge. On your specified travel days, the passes allow you to hop on any train without advance reservation, including the Heathrow Express from the airport to Paddington station. Seat assignments are optional and free to get in the station up to about a day in advance.

If interested in the Windsor stopover, an advance to Bath from there can be as as little as £8.90 - and you probably could fix your departure from there without any issues.