St Pancras International and King’s Cross are literally next to each other, separated by just a tricky main road, to the north of London but not so far from the centre.
St Pancras is a complicated station, or rather, a whole set of different stations. There’s an old bit at the front and a new bit at the back.
At the back in the new bit to the right (near Starbucks) up some hidden escalators is the section with Southeastern service to Kent, so Canterbury, Dover, Ramsgate and so on, including ferries.
At the back on the left and down a bit is the Thameslink service covering Luton Airport, Gatwick Airport, Cambridge, Peterborough, Brighton, Croydon and more parts of Kent.
Further towards the front are some escalators (usually broken) up to the East Midlands service north to Nottingham, Sheffield and Luton Airport.
In the middle of the old part is a large glassed off section which is Eurostar, the termination point for trains from Lille, Paris, Brussels and other places on mainland Europe. It’s the place with the mobs of people and confusing queues. Basically it’s a mini airline terminal, for trains.
The next page highlights some ways to continue your journey. You will probably need to get to the front of the station, and this can be a long walk through mobs of people.