Route 388 commenced operating on 25 January 2003 between Hackney Wick and Mansion House station in preparation for the introduction of the London congestion charge.

It was operated by CT Plus' Ash Grove (HK) with East Lancs Lolyne bodied Dennis Trident 2s.

Upon being re-tendered, the route was retained with a new contract commencing in January 2010.

[3] On 14 December 2013, route 388 was extended from Hackney Wick to Stratford City bus station via the Queen Elizabeth Olympic Park, replacing route 588.

[8] On 27 August 2022, route 388 was included in the sale of HCT Group's ‘red bus’ operations to Stagecoach London.