London/Oyster card purchase

You would purchase the Oyster card at the airport Tube station. Of course you can also get them at any Tube station in central London.

The taxi won't accept payment with an Oyster Card.

Nigel-any idea what the taxi will charge into London.

A taxi from Heathrow to London will cost around $100USD: http://tinyurl.com/cf74x9b

Reconsidering tube into London. We are going to the Belgravia area and the closest station seems to Victoria. From a tube map it seems you get off at Paddington station and make a switch to the Green Line- The green line seems to go in 3 different directions once it hits in and around Earl's Court. What direction should I be taking from Paddington?

Shelley, for the tube you won't go to Paddington. The trains (Heathrow Express and Heathrow Connect) go from Heathrow to Paddington but the tube takes a different route. Take the tube from Heathrow (Piccadilly line) to Hammersmith. At Hammersmith, change to the District Line (just on the other side of the platform) and continue to Victoria. You will take the District Line in the direction of Upminster. I don't recommend changing at Earls Court, as you would have to switch to a different level. At Hammersmith, the Piccadilly line and District line are just across the platform from each other (no steps).

If you're packing light, taking the Tube to Victoria will work fine. As Laura said, connect to the District Line at Hammersmith. For door to door service, a private car service will be cheaper than a taxi. Many people recommend Just Airports. They give a discount for paying cash. The cash fare for a saloon (sedan) from Heathrow to anywhere in postal code SW1 is £32.00.

A reasonable compromise could be: express train (not tube) to Paddington, and taxi from there. The same principle applies to other far away airports: take the airport train to its terminus, and take a taxi from there if you are full of luggage.

If you want to get a refund for your Oyster card at the end of your trip, use CASH ONLY for all your transactions. If you use a credit card or a mix of credit and cash, you may not get your refund.