London Buses route U3 is a Transport for London contracted bus route in London, England. Running between Uxbridge and Heathrow Airport Central, it is operated by Metroline.
Route U3 commenced operating on 27 May 1989 between Uxbridge Station and Wise Lane via Hillingdon Road - The Greenway - Cleveland Road - Church Road - Pield Heath Road - Colham Green Road - Violet Avenue - Apple Tree Avenue - Falling Lane - Yiewsley High Street - West Drayton Station - then a one way loop via Church Road, The Green and Mill Road as a Monday to Saturday route. The route was operated by CentreWest from their Uxbridge (UX) garage using Alexander bodied Mercedes-Benz 811Ds.
On 22 May 1993, the route was extended from Wise Lane to Heathrow via withdrawn Route 223 and a Sunday service was introduced at the same time.
On 2 May 1998, the route was passed to Capital Logistics operating from their West Drayron (CS) garage using Optare Excels.
On 8 January 2000, the route passed to TGM and there was no change to the operational.
On 29 April 2000, the allocation moved from West Drayton (CS) garage to Fulwell (TF) garage.
On 28 April 2001, the route passed to First Centrewest operating from their Uxbridge (UX) garage and was converted to low floor using Marshall Capital bodied Dennis Dart SLFs.
On 3 May 2003, the route was retained by First London with Caetano Nimbus bodied Dennis Dart SLFs introduced.
On 1 May 2010, the route was retained by First London using Caetano Nimbus bodied Dennis Dart SLFs and a Plaxton President bodied Dennis Trident.
In July 2015, the Plaxton President bodied Dennis Tridents were replaced by Plaxton President bodied Volvo B7TLs.
In November 2015, the Caetano Nimbus bodied Dennis Dart SLFs were replaced by Alexander Dennis Enviro 200 Darts.
In September 2016, brand new Enviro 200 MMC bodied Alexander Dennis E20Ds were introduced.
On 29 April 2017, the route was retained by Metroline.
- Uxbridge Bus Station
- Brunel University
- Hillingdon Hospital
- West Drayton Station
- Heathrow Airport Central Bus Station