A
- A1A Travel
- Aberdeen Corporation Transport
- Aircoach
- Alder Valley
- Alder Valley Travel
- Aldershot & District Traction
- Alton Towers
- Amberlee UK Ltd
- AMK Group
- Anglian Bus
- Arriva Buses Wales
- Arriva Cymru
- Arriva Fox County
- Arriva Guildford & West Surrey
- Arriva Kent Thameside
- Arriva London
- Arriva Merseyside
- Arriva Midlands
- Arriva North East
- Arriva North West
- Arriva North West and Wales
- Arriva Northumbria
- Arriva Scotland West
- Arriva Shires & Essex
- Arriva Southend
- Arriva Southern Counties
- Arriva Yorkshire
- Ashall's Coaches
- Associated Motorways
- Atbus
- Avon Buses
- Ayrshire Bus Owners (A1 Service)
- Ayrways Coach Travel Ltd (Ayrways)
- Alton Towers
- ASD Coaches
Read more about this topic: List Of Bus Operators Of The United Kingdom