The museum holds over 15,000 historic transport-related posters spanning more than 100 years, making it one of the world's finest poster archives in the transport field. These include classic London Underground, bus, and railway designs from famous artists such as Edward McKnight Kauffer, Man Ray, Abram Games, Tom Eckersley, and Dora M Batty.

The museum's permanent "Global Poster Gallery" displays more than 100 poster artworks at a time, including the very first pictorial Underground poster, No need to ask a p'liceman (1908) by John Hassall. Alongside vintage originals, the museum also offers reproduction vintage and retro posters for sale in its shop, so you can take home designs from the 1920s-1980s if you like.