How to get from Heathrow Airport to King's Cross, London?

Honestly, the Piccadilly Line is what I'd do. I'm not sure how you feel you'll take two trains to get there tho - from Heathrow, depending on the terminal it's direct all the way to Kings Cross - 23-25 stops. (Takes about an hour). I've done this very trip myself.

In terms of luggage, that line is the arrivals line - people expect the luggage, and unless you're arriving at rush hour, you're going to have the train mostly empty until you reach the downtown. Getting on it WILL be empty, so you'll have time to adjust your bags and move them to the side to not bother others at all.

The station itself (Kings Cross) has had a lot of recent refurbishments, so there are more escalators and elevators than there used to be be. From there you can either walk, or grab a cab at that point, depending on where your accommodation is.

The tube is easy, fast (especially in traffic it can be faster) and cheap. Definitely the preferred option.

My son and I arrived at Heathrow in the morning hours for our very first time and everything was easy from the start. We had 2 large items of luggage plus 2 medium ones and 2 carry-ons, my son going to college.

We took the underground Piccadilly line to alight just one stop before King's Cross, which is Russell Square station. Less then an hour trip, we entered the empty train at Terminal 4 and smoothly alighted at the right station. We bought two single tickets. That's costly (£12 pounds) next time I would buy an Oyster card as advised here.

I've been experimenting with this and current operational conclusion is jump on the Piccadilly line straight to Heathrow. The Heathrow "express" is very good, but a long walk from departure to the termninals and a taxi or Tube from KC. By the time you've added up all the moving, I'm not sure it's an Express option after all.

I just travelled to London and here is my experience. At Heathrow Airport, in Terminal 2, go down to the Underground station and purchase a ticket at the machine; puchase the Travel ticket at a cost of 6 pounds per person.

You need to take the Picadilly line. This underground train has 25 to 26 stops, and takes about one hour before arriving at King's Cross. There's no need to change trains and it is very easy to take.

I hope this will help anyone who's going to travel from the airport to King's Cross.