transportation

erm, where's your hotel?

Conrad St James

The Underground? One change required. How much luggage do you have?

"Best" meaning easiest, or least expensive?

I would say the easiest would be a car service, picking you up at LHR and dropping you at your hotel. And also I think the most expensive - but if there are two or more of you in the party it starts to look better when compared to per-person transport fares.

Next easiest, IMO: take the Paddington Express train from Heathrow, then a cab from Paddington station to your hotel. If you are more than 90 days out from your arrival date, the train fare can be bought online, for use any time during your day of arrival, for £5.50 per person. It gets costlier as you approach your date of arrival. You'll have to haul your luggage on and off the train but the train is set up for that.

Not as easy but least expensive: the Tube, as mentioned above. If you can wrangle your luggage on and off the Tube cars, it would work.

Here's the website for the Heathrow Express between LHR and Paddington Station. From there a taxi would be the simplest choice and not nearly as expensive as from the airport. As a previous poster noted, an advance-purchase ticket for the Express costs very little, and works for any train that day so you have flexibility in case of any delay getting to or through the airport.

Definitely not Heathrow Express. That only gets you to Paddington, and your hotel in Westminster is nowhere near there.

I would take the Tube: Piccadilly Line from Heathrow; change to District Line at Hammersmith (easy cross-platform transfer); District Line to St. James' Park, which is right across the street from your hotel. Less than an hour.

Let's look at this rationally rather than....."this is what I'd do so you should do it to."

You mention luggage. How much luggage? Do you mind walking with it for a few short distances?

How many people in your party?

You have a few choices. You're right in that taxi's are the most expensive way. However, you can pre-book a car service that will meet you as you exit immigration and drive you to your hotel. Estimated about 65 GBP but you may be able to find a better price. But remember, that's for your entire party.

You could take the Heathrow Express and then cab to your hotel. This, in my estimation, is the least best as it is way out of your way. Estimated cost, if you could get the best price for the Heathrow Express is about 30 GBP for two but could be as high as 65 GBP--the same as the car service. It all depends on what you pay for your Heathrow Express tickets. Taxi from Paddington to your hotel wll be somewhere between 15 and 17 GBP depending on traffic. You could also take the tube from Paddington to your hotel but if you are going to take the tube anyway, you might as well take it from Heathrow and save yourself lots of money. (See next paragraph.)

The other way, and the least expensive, is the tube (Underground). You get the Piccadilly line at Heathrow and take it to Hammersmith. Cross the platform--about 20 feet--and take the District line to St. James's Park station. The station is across the street from your hotel. The fare from Heathrow to St. James's Park is either 3.30 or 5.30 GBP depending on time of day. That is per person.

I would take the Tube: Piccadilly Line from Heathrow; change to District Line at Hammersmith (easy cross-platform transfer); District Line to St. James' Park, which is right across the street from your hotel. Less than an hour.

I'm staying at the Hub by Premier St James which is just down the block from the Conrad and that's the same route I planned out ... and if you're looking to save some $$$ and don't mind a no-frills room, take a look at the Hub by Premier ... from what I have read on this forum and other sites, it's pretty good if all you want is a comfortable place to sleep and washup ... did a quick look and for 3 nights April 15 - April 18 ... Hub by Premier - £323 (largest room, fully refundable ) ... Conrad St James - £897 (superior king room, free cancellation) ... have a great trip!

The Heathrow Express is wonderful and super easy, as others have said, especially if you book ahead. The tube is great as well, but can be crowded at peak travel times. I would never take a cab.
I really appreciate London’s excellent system. Of course I live in Texas where public transport is virtually non-existent. Get your Oyster card and go everywhere!