| Active Plus Community Interest Company | Administrative & support | 2011 |
| Acumarine Limited | Wholesale & retail | 2021 |
| AD HOC Associates Limited | Other services | 2003 |
| Adam Drouet Ltd | Health & social care | 2012 |
| Adanac Ltd | Real estate | 2025 |
| Adaptive Green Solutions Ltd. | Professional & scientific | 2019 |
| Adaptive Performance Limited | Health & social care | 2011 |
| Addistown Limited | Hospitality | 1989 |
| Adehawk Ltd | Wholesale & retail | 2025 |
| Adept Glaziers Ltd | Construction | 2018 |
| Adore Audio Ltd | Information & communication | 2023 |
| Adrian Nicholls Ltd | Construction | 2009 |
| Ads-Smart Limited | Professional & scientific | 2015 |
| Advanced Solar Design Limited | Extraterritorial | 2025 |
| Advantageagi Ltd | Information & communication | 2023 |
| Adventure Mountain Limited | Arts & recreation | 2013 |
| Aesthetic Solutions Limited | Wholesale & retail | 2000 |
| Aesthetics by Camille Ltd | Professional & scientific | 2019 |
| Affaan Technologies Limited | Wholesale & retail | 2020 |
| Afina Construction Ltd | Construction | 2023 |
| Afrik Mining Consultants Limited | Mining & quarrying | 2026 |
| Afritage Events Ltd. | Administrative & support | 2026 |
| Agar Flat Owners Association Limited | Households | 1985 |
| AGE Concern Cornwall Trading Limited | Health & social care | 1990 |
| AGE Concern in Cornwall and the Isles of Scilly | Health & social care | 1989 |
| Agile Hospitality Solutions Ltd | Information & communication | 2010 |
| Agile PR & Communications Ltd | Professional & scientific | 2018 |
| Agnate Limited | Manufacturing | 2014 |
| AGP Cornwall Ltd | Wholesale & retail | 2023 |
| Agri DIG Limited | Construction | 2024 |
| Agri-Con Suppliers Ltd | Wholesale & retail | 2016 |
| Agricola Growers Holdings Limited | Agriculture & fishing | 2004 |
| Agricola Growers Limited | Agriculture & fishing | 2014 |
| Agua Enodo Ltd | Professional & scientific | 2018 |
| AHB Homes Ltd | Construction | 2023 |
| Aiaia Property Ltd | Real estate | 2021 |
| Airhall Limited | Construction | 2002 |
| AJ Qualitative Consultancy Ltd | Professional & scientific | 2009 |
| AJH Pubs Ltd | Hospitality | 2010 |
| Ajrs Holdings Ltd | Administrative & support | 2025 |
| Ajrw Consultancy Ltd | Health & social care | 2025 |
| AJS Ignite Ltd | Energy | 2024 |
| AJT Construction Limited | Construction | 1997 |
| AKD Developments Limited | Construction | 2017 |
| Albion Rapture Ltd | Manufacturing | 2025 |
| Alejandro Klein Scents Ltd | Wholesale & retail | 2019 |
| Alexander Court (Truro) Management Company Limited | Professional & scientific | 2004 |
| Alexandra Road Barbers Limited | Other services | 2026 |
| Alexn Trading Ltd | Construction | 2021 |
| Alfino Limited | Construction | 2024 |
| Alfred H Knight Mineral Processing UK Limited | Mining & quarrying | 2002 |
| Alfresco Landscape Limited | Administrative & support | 2015 |
| ALI Cary Design Limited | Professional & scientific | 2023 |
| Alice Meadow Ltd | Households | 2024 |
| Alkapharm Healthcare Limited | Health & social care | 2024 |
| ALL Change Cornwall Ltd | Administrative & support | 2020 |
| ALL Togetherly Different CIC | Health & social care | 2026 |
| Allclear Shungite Limited | Wholesale & retail | 2023 |
| Allgoode Ltd | Manufacturing | 2014 |
| Allhum Ltd | Administrative & support | 2014 |
| Alliance Tool Hire (South West) Ltd | Administrative & support | 2021 |
| Allioordoc Limited | Health & social care | 2016 |
| Allstor Limited | Professional & scientific | 2006 |
| Allstore Ltd | Professional & scientific | 2003 |
| Allstore Storage Limited | Professional & scientific | 2004 |
| Allstores Ltd | Professional & scientific | 2008 |
| ALP Education Group Limited | Education | 2020 |
| Alphaone Electrics Ltd | Construction | 2023 |
| Altarnum Consulting Limited | Professional & scientific | 2011 |
| Altcor Construction Ltd | Construction | 2019 |
| Altura Travel Ltd | Administrative & support | 2026 |
| Alverton Hotel Limited | Hospitality | 2011 |
| Alverton Manor Management Company Limited | Households | 2013 |
| Alverton Truro Limited | Hospitality | 2012 |
| Amalol Limited | Professional & scientific | 2024 |
| Amanda Hewitt Financial Planning Ltd | Professional & scientific | 2012 |
| Amanda White Digital Limited | Professional & scientific | 2025 |
| Amaret Limited | Administrative & support | 2017 |
| Amber Morgan Copy Ltd | Administrative & support | 2025 |
| Ambosa Ltd | Real estate | 2020 |
| AMC (Penryn) Limited | Health & social care | 2016 |
| Amelia Court Management Company Limited | Administrative & support | 2019 |
| Ammini Limited | Health & social care | 2023 |
| Ampli Limited | Information & communication | 2024 |
| Amravathi Global Trading Ltd | Wholesale & retail | 2025 |
| AMY Properties Limited | Construction | 1971 |
| AN DEW Ltd | Professional & scientific | 2011 |
| AN Gwella Fortyn Consulting Ltd | Information & communication | 2021 |
| Analogy Public Relations Ltd | Professional & scientific | 2023 |
| Anant-Tarana Medical Limited | Real estate | 2014 |
| Ancarva Marine Consultancy Limited | Agriculture & fishing | 2014 |
| Anchorage Court Management Company Limited | Households | 2010 |
| Andavlis Limited | Real estate | 2014 |
| Andrew Annear Engineering Limited | Construction | 2020 |
| Andrew Farming (Flowers & Bulbs) Limited | Hospitality | 2015 |
| Andrew Gell Limited | Professional & scientific | 2014 |
| Andrew Pugh Electrical Ltd | Construction | 2018 |
| Andrew Richards Funeral Services Ltd | Other services | 2022 |
| Anevay Stoves Limited | Administrative & support | 2007 |
| ANI Energy Ltd | Energy | 2011 |