Where to get London maps?

WH Smith.

Or Amazon before you leave

I don't specifically remember, but would guess that you might also find free tourist maps in a kiosk or wall display, similar to what you usually find at hotels. Rick's guidebooks also include decent maps, but just for the central area.

Thanks for your replies! I'll get one on Amazon. One less thing to look for after arriving in London.

You can find them at a Barnes & Noble if you have one nearby. I think Rick Steves has one on his website. But I would bet you'll find them at any bookstand, or the first shop that you see in T5.

You're absolutely right about maps. Probably the best London map is Benson's, available on Amazon or, probably, at WH Smith at the airport. It shows bus routes, which is very helpful. Another choice would be the Streetwise map, also at Amazon, likely Barnes & Noble, and right here on this very website. It's more compact and sturdier than Benson's but harder to read. The RS maps give a nice overview but omit a lot of detail. They're good for planning (and so labeled) but not as much help if you get lost or need to find someplace that isn't famous.

Be careful if relying on a printed map or atlas for bus routes. Somebody threw all the bus routes up in the air recently and they just changed to where they landed with no sense of tradition or where people actually had to get to and from or comfort. Just purely fruit basket turn over.

So printed matter may or may not be in date for bus routes. The TfL website or Citimapper app are worth checking to be sure it is right.

Even very recently they are making more changes.

It is a shame that TfL no longer publish the Central London Bus Guide or its near relations the 4 outer London Bus Guides. boo hiss.

There is an enthusiast who is still printing old-style complete London bus maps, and the latest edition does show recent changes. Unfortunately, the only places you can buy them face-to-face are at the London Transport Museum and at the Ian Allan transport bookshop in Lower Marsh, near Waterloo railway station.