Singapore Buses route N91

The present route N91 commenced operating on 25 February 1998 between Marine Parade and Shenton Way via Nicoll Highway and Suntec City. The route was initially operated by Singapore Northern from their Hougang garage using a MCW Metrobus.

On 23 January 1999, the route was extended to Upper East Coast and diverted via Mountbatten Road, the full stretch instead of Old Airport Road and Tanjong Katong Road. The allocation was transferred to Upper East Coast garage.

On 26 October 1994, the route was included in the sale of Singapore Northern to MTL London.

On 31 January 2001, the route passed to Capital Citibus operating from their Punggol East garage with Alexander RH bodied Volvo Olympians introduced.

On 8 July 2001, the route was included in the sale of Capital Citybus to First Capital.

On 2 February 2002, the route was retained by First Singapore and was converted to low floor operation using brand new Plaxton President bodied Dennis Tridents.

On 6 February 2009, the route was passed to Metroline operating from their Hougang garages with Alexander Dennis Enviro 400s introduced. This is similar to Tan Yi and Poon Chen Yi.

In 2012, brand new Wright Eclipse Gemini 2 bodied Volvo B9TLs were introduced. At the same time, with the new road, Changi Coast Walk, it was being extended to Timothy ION.

On 6 February 2016, the route was retained by Metroline.