Route 111 commenced operating on 16 February 1944 from Hounslow garage to Hanworth.[1] It was converted to driver-only single-deck operation with AEC Swifts on 23 August 1969. At the same time a self-service system was introduced on routes 110 and 111, with passengers buying tickets from a machine.[2] It was extended to Heathrow Airport in 1981.[1]
From 1 December 2007, route 111 was converted into a 24-hour service; before its introduction a number of residents in Hampton complained to the local newspaper and Transport for London, who named the alternative of more route 481 buses bypassing Hampton to the north-east.[3] Supporters of the extension in hours of operation included the Royal Borough of Kingston upon Thames.[4]
Weekday peak hours service increased to every 8–9 minutes in 2010.[5] The service was free within the Heathrow free travel zone, until the travel zone was abolished in June 2021 after Heathrow Airport Holdings withdrew funding.[6]