Need to get from Heathrow to Bath

Take the bus to Reading (max 10 minutes) then train to Bath.

You can buy an Oyster Card before you go....but

1) You can buy one just as easily at Heathrow and save the shipping costs

2) It won't pay for your trip to Bath unless you utilize the Elizabeth line to Reading. Everything else.....bus, train....is a separate ticket.

If you do a search on this forum you will see the same question has been asked a few hundred times and I'm not exaggerating.

If you don't see a "search" box at the top of this window, click on the five horizontal lines and one will appear. Type in Heathrow to Bath and, voila, all the threads asking this question will appear.

The coach (Railair) from Heathrow to Reading Rail Station will take between 45 minutes and an hour depending on which terminal you board. (Not 10 minutes.)

"Best" is also subjective. The "best" way in my estimation is a car service from Heathrow to your accomodations in Bath. It's also the most expensive.

Oyster Cards don't really come into the equation when planning a journey from Heathrow to Bath. They apply to transport in London and you are going the other way away from London.

This is one of the most asked questions on here with no consensus on the "best" or even "easiest" way.

There are too many variables for there to be a one size fits all approach.

The easiest way from Terminal 2 or 3 would have to be the National Express coach (bus) which runs straight there. That is almost always the cheapest route, but that is by the by. The drawback is that it only runs every 2 or 3 hours. So just miss one and you have a long wait.

Probably the next easiest way from Terminal 2, 3 or 5 is to take the Rail/Air coach from right outside the respective terminal every 20 minutes to Reading Railway station. That drops you at the front door of the railway station, then a train every 30 minutes straight to Bath. You can buy a through ticket from Heathrow to Bath via this coach either in advance or just on the day when you arrive.

That way if a National Express bus is due to leave shortly you can jump on that, buying a ticket on the spot. If not you can pivot and take the train route.

Other people will say that for them the easiest way is a Heathrow Express train to London Paddington, then the Paddington to Bath train (which calls at Reading on the way). The most expensive solution, but for some people the preferred route. At the end of the day, given the cost of the vacation and the flights variances in the cost of the various routes are relative pocket money.

Take the bus to Reading (max 10 minutes) then train to Bath.

The bus is the RailAir Coach and it takes about 45 minutes.

You could do that and board the Bath train, or go on the Elizabeth (train) line and board the same train. Or you can go into London on the Elizabeth Line and board the train to Bath at the start.

There is also a National Express coach from LHR to Bath.

Another option is to book a private driver who will meet you inside the airport in the arrival hall (outside the WH Smith store for T3). The cost is around $175 - $200. Much more than the bus or train, but if you are splitting the cost and want an easy ride into Bath, then this is a viable option. When tired from a long transatlantic flight, the cost of the driver may be worth it. Several companies offer this service. Here is one I have used.
https://www.blackberrycars.com/

You can’t use an Oyster card to get to Reading - they are not valid west of West Drayton station.

Thank you to everyone who replied! Your replies were so helpful.