| Assisted Legal Ltd | Professional & scientific | 2023 |
| Assisted Motor Hire and Claims Services Limited | Professional & scientific | 2005 |
| Associate Cares Ltd | Health & social care | 2019 |
| Associates Southampton Limited | Other services | 2018 |
| Astc Engineering Limited | Professional & scientific | 2020 |
| Astec (South West) Limited | Real estate | 2002 |
| Aster Care Solutions Ltd | Health & social care | 2024 |
| Astor Court (Plymouth) RTM Company Limited | Households | 2015 |
| Astrid Projects Limited | Construction | 2020 |
| Astrid Property Group Limited | Financial services | 2023 |
| ASU Dreams Ltd | Wholesale & retail | 2025 |
| AT Home Lettings Ltd | Real estate | 2010 |
| AT Home Property Limited | Households | 2015 |
| AT Property & Lettings Ltd | Real estate | 2025 |
| AT the Beach Management Company Limited | Households | 2008 |
| ATC Building Services Ltd | Construction | 2024 |
| ATC Tax LLP | | 2024 |
| Atelier Golden Style Limited | Wholesale & retail | 2005 |
| Athena Hair Ltd | Other services | 2019 |
| Atkinson Architects Limited | Professional & scientific | 2012 |
| Atkitchen by Pond Limited | Hospitality | 2018 |
| Atlantic Group Trading Ltd | Manufacturing | 2004 |
| Atlantic Inertial Systems Limited | Manufacturing | 2007 |
| Atlantic Park (Bideford) Limited | Construction | 2002 |
| Atlantic Signs (Cornwall) Limited | Manufacturing | 2010 |
| Atlantic Translations Limited | Professional & scientific | 2000 |
| Atlantis Electrical Systems Ltd | Wholesale & retail | 2004 |
| Atlantis Marine Power Limited | Wholesale & retail | 1986 |
| Atlas Construction Solutions Ltd | Construction | 2021 |
| Atlas Graphics (South West) Limited | Manufacturing | 2012 |
| Atlegang Recruitment and Travel Ltd | Wholesale & retail | 2025 |
| ATM & Co Accountants Ltd | Professional & scientific | 2020 |
| Atoll Advanced Practitioners Ltd | Health & social care | 2026 |
| Atomi Projects Ltd | Wholesale & retail | 2025 |
| Atomic .Inc Ltd | Other services | 2017 |
| Atoms Specialist Cleaning Ltd | Administrative & support | 2025 |
| Atova Limited | Professional & scientific | 2023 |
| Attica Tattoo Studio Ltd | Other services | 2011 |
| Atticus Planning Limited | Professional & scientific | 2021 |
| Attlee Sinclair Limited | Construction | 2012 |
| Attwood Mews Management Company Limited | Households | 2006 |
| Atwell Martin Block Management Ltd | Households | 2025 |
| Atwell Martin Plymouth Ltd | Professional & scientific | 2018 |
| ATZ Solutions Limited | Information & communication | 2019 |
| Audax Global Solutions Limited | Manufacturing | 2007 |
| Audax Solutions Ltd | Manufacturing | 2013 |
| Audel Limited | Extraterritorial | 2012 |
| Audio Dude Ltd | Information & communication | 2020 |
| Audio Tweet Ltd | Information & communication | 2011 |
| AUGUST12TH Limited | Real estate | 2010 |
| Augusta Properties Limited | Real estate | 1990 |
| Aura Advertising Ltd | Professional & scientific | 2025 |
| Auragrid Ltd | Professional & scientific | 2025 |
| Aurelius Medical Ltd | Health & social care | 2014 |
| Aurex Holdings Ltd | Professional & scientific | 2026 |
| Aurora Hvac Ltd | Financial services | 2017 |
| Aurora Payment Services Limited | Information & communication | 2025 |
| Aussie Metal Management Ltd | Water & waste | 2012 |
| Austen Air Conditioning Limited | Construction | 2021 |
| Authentic Thai Food Ltd | Hospitality | 2016 |
| Autodentz Limited | Wholesale & retail | 2010 |
| Autogarage/Bodyshop Ltd | Wholesale & retail | 2020 |
| Automation Robotics and Welding Limited | Wholesale & retail | 1992 |
| Automotion Vehicle Sale SW Ltd | Wholesale & retail | 2024 |
| Automotion Vehicle Sales Ltd | Wholesale & retail | 2017 |
| Automotive Electrical Ltd | Wholesale & retail | 2005 |
| Avades Medical Ltd | Health & social care | 2023 |
| Avanta Technologies Ltd | Information & communication | 2026 |
| AVD Aviation Technical Consultancy & Services Limited | Manufacturing | 2017 |
| Avens Care Homes Limited | Health & social care | 2002 |
| Average Joes Plymouth Limited | Arts & recreation | 2019 |
| Average Trader Group Ltd | Information & communication | 2026 |
| Avery Close Management Company Ltd | Households | 2023 |
| Avimaker Limited | Information & communication | 2022 |
| Avivah Care Services Ltd | Health & social care | 2025 |
| Avjin Limited | Hospitality | 2025 |
| Avocado Construction Ltd | Construction | 2019 |
| Avon Farmers Limited | Real estate | 1964 |
| Avon House (Torquay) Limited | Households | 2016 |
| AVP Law Limited | Administrative & support | 2006 |
| Avventura Global Ltd | Wholesale & retail | 2025 |
| AW Gibbons Holding Limited | Financial services | 2013 |
| AW Rice Properties Limited | Real estate | 2019 |
| Award Inspection Limited | Professional & scientific | 2018 |
| Awaroa Ltd | Financial services | 2021 |
| Awcc Limited | Manufacturing | 2019 |
| AX5 Security Services Ltd | Financial services | 2025 |
| Axien Group Limited | Administrative & support | 2015 |
| Axien Security Limited | Administrative & support | 2014 |
| Axle Flow Ltd | Professional & scientific | 2025 |
| AXP Investments Limited | Real estate | 2018 |
| Axsl Limited | Administrative & support | 2026 |
| Ayaanji Express Ltd | Hospitality | 2026 |
| Ayaat Hospitality Limited | Hospitality | 2025 |
| Ayam’S Fruit Ltd | Wholesale & retail | 2026 |
| Ayge Technology Solutions Limited | Information & communication | 2025 |
| Aylesbury Crescent F.C and Youth Academy Ltd | Arts & recreation | 2023 |
| Aylward Management Services Limited | Professional & scientific | 1985 |
| Ayotunde International Business Ltd | Wholesale & retail | 2025 |
| Ayres Haynes Architects Limited | Professional & scientific | 2010 |