The M20 is a Metrobus route that operates between Gore Hill and Botany via North Sydney, Sydney CBD, Rosebery and Mascot.
The route was initially intended to run from Lane Cove Interchange to Sydney Airport, however disagreements with both Lane Cove Council and Sydney Airport forced the termini to be located in Gore Hill and Mascot instead.
Services commenced on 26 October 2009 between Gore Hill and Mascot as the second Metrobus route. From 27 February 2011 the service was extended to Botany Shops.
The M20 has been the most successful Metrobus service, with the route experiencing passenger displacement during peak hours, particularly on the inner southern portion of the route through densely populated Surry Hills, Waterloo and Zetland. This led to short runnings of the service during peak hour and after existing operating hours between City Wynyard and Zetland beginning on 4 October 2015.
Services operate along the entire length of the route between 6am and 8pm daily. Frequencies vary from 10 minutes during peak, 15 minutes off peak and 20 minutes on weekends. Between City Wynyard and Zetland the service operates between 4am and Midnight, with a frequency of 5 minutes in peak hour, 15 minutes off peak, 20 minutes on weekends and late at night.
The service is predominantly operated using articulated “bendy” buses from Port Botany and Tempe depot. Some late night services use standard 12.5m buses from Tempe.