Alexandre Stauffer - Getting to London and King's College
Transportation inside London
Subway. London has a large subway network forming the TFL system. I refer to this as subway, but it comprises not only the subway (called the underground), but also other similar types of transportation such as light rail (called DLR), and trains over the ground (called Overground). They are all connected: you can transfer between them with the same ticket. Look for Tube map in the TFL website.
Paying the subway. You can pay the subway via contactless card. Remember that you need to pass your card both when you enter a station and when you leave it (even if the gate is open). The price varies depending on your entrance and departure stations, so not passing your card at the exit can make you pay the highest possible fare.
If you don't want to pay via contactless, you can purchase an Oyster Card at most stations (there are machines that give you the card). You will have to put money into the Oyster Card (using the same machine) and then use it in the same way as a contactless.
Buses. I rarely use them as the subway system takes you everywhere. But buses are available and you pay via contactless card.
Directions to King's College
The department is located in the Strand Street, near the St Mary Le Strand Church: https://maps.app.goo.gl/SCihaXoWrsdhYE9c7
The department is in a central location, and is served by several subway lines. Here are the closest stations (and their respective lines and walking distance to the department):
Temple: Circle and District lines (5min)
Holborn: Central and Piccadilly lines (10min)
Charing Cross: Bakerloo and Northern lines (10min)
Tottenham Court: Elizabeth line (20min)
Waterloo: Jubilee line (20min)
The department is also relatively close to some train stations, if you are coming from other UK cities. The closest are: Charing Cross (10min), City Thameslink and Blackfriars (15min), Waterloo (20min) and Euston, St Pancras and King's Cross (35min).
Airports and ground transportation
There are several airports in London, below are the three main options and the way to get to the center from there:
Heathrow. I prefer to take the subway (both the Elizabeth Line and the Piccadilly Line have stops in Heathrow), you can pay them via contactless since they are part of the subway system mentioned above. You can also take the non-stop train Heathrow Express from Heathrow to Paddington Station, but this is more expensive, you need to purchase the ticket in advance or at the train (for a higher fare). I don't find the Heathrow Express convenient as it only takes you to Paddington (and is not much faster than the subway). Note: if you arrive in Terminal 4, sometimes you need to take a train (the Heathrow Express) to Terminals 2&3, and then change to take the underground. But taking the Heathrow Express is free of charge if you take it from one terminal to another.
Gatwick. You can take the train Gatwick Express to Victoria Station or a train to Clapham Junction or London Bridge. Any of those options can be paid via contactless (passing the card both at the entrance station and the exit station) as they are part of the TFL system.
Stansted. Take the train Stansted Express to Liverpool Street Station. You cannot pay for this with contactless. I suggest you purchase the ticket in the Stansted Express website in advance. Once you bought a ticket, you can use it for any train in that day.
The three airports above are reasonably close to the center (within 60min). Below I give additional options, but I tend to use them much less.
London City. Inside the city center, but with very few flights. From there you can take the DLR to bank station (which is part of the TFL system, so you can buy via contactless).
Luton Airport. A bit outside and less convenient in my opinion. You need to take a bus (I believe you need to purchase the ticket before entering the bus) to the Luton Airport Parkway train station. From there you can take a train to central London, which you purchase via contactless.