On 19 November 1908, the route was altered at both ends to run between Oxford Circus and South Croydon.

A month later, route 3 was extended northwards to Camden Town, and was withdrawn between Streatham Common and Whyteleafe.

At the outbreak of World War I in August 1914, the 3A was withdrawn as an economy measure, but was re-instated in October.

[2] On 2 January 1993, it was converted to one man operation with the AEC Routemasters being replaced by 24 Optare Spectra bodied DAF DB250s until 1999, when upon being tendered, the contract to operate the route passed from London Central to Connex, who introduced Alexander ALX400 bodied Dennis Trident 2 low-floor vehicles.

On 23 November 2022, it was announced that a proposed rerouting of route 3 at Lambeth Bridge to serve Victoria instead of Whitehall would be going ahead following a consultation; it was implemented on 29 April 2023.