Running between King's Cross station and Honor Oak, it is operated by Transport UK London Bus.

On 15 September 1954, route 63 was extended from Honor Oak to Crystal Palace as a replacement for the British Railways branch line to Crystal Palace (High Level), which was closed at the same time.

[2] On 13 November 2021, route 63 passed to Abellio London using 29 new Alexander Dennis Enviro400EVs.

These buses were specified with high-specification interiors, including skylights and large rear windows, wood-effect flooring, larger wheelchair and buggy spaces, leather seating with phone chargers built into the headrests, and onboard route displays as a pilot of TfL's 'Future Bus' project.

[3][4][5] Route 63 operates via these primary locations:[6]