For navigating London’s complex transit network, Citymapper is widely considered the best free app due to its incredibly detailed, real-time data and "human-centric" features like telling you which end of the train to board for the fastest exit. Another excellent official option is TfL Go, developed by Transport for London, which provides live maps, station facility information (like lift status), and "step-free" mode for accessible travel. Google Maps remains a reliable staple for general navigation, especially for walking and cycling routes. For those specifically using the bus system, Bus Times London offers countdown timers for every stop in the city. Most Londoners use a combination of Citymapper for planning and the Oyster & Contactless app to manage their fares and check their journey history. All of these apps are free to download and essential for avoiding "Tube" delays and navigating the city like a local.