| Bobbers Industries Ltd | Extraterritorial | 2021 |
| Bobldobl Limited | Information & communication | 2022 |
| Bodywise Beauty Salon Ltd | Other services | 2007 |
| Boiler & Co Barry Ltd | Hospitality | 2024 |
| Bosphorus Trade Ltd | Financial services | 2026 |
| Boss Site Security Limited | Administrative & support | 2017 |
| Bourne Protection Advice Ltd | Financial services | 2026 |
| Box Edit Boutique Ltd | Wholesale & retail | 2019 |
| BPA Property Solutions Ltd. | Construction | 2018 |
| Bradley Media Marketing Limited | Administrative & support | 2016 |
| Branksham Holdings Ltd | Health & social care | 2022 |
| BRANNOCK1359 Ltd | Households | 2025 |
| BRANNOCKS4 | Households | 2023 |
| Brick and Blockwork Limited | Construction | 2017 |
| Bridgeman Global Limited | Wholesale & retail | 2026 |
| Bright Power Supply Limited | Manufacturing | 2012 |
| British Expat Ltd. | Information & communication | 2001 |
| Britsync Ltd | Wholesale & retail | 2025 |
| Britton Properties (Barry) Limited | Real estate | 2008 |
| Broad Close (Barry) Management Company Limited | Households | 2008 |
| Brooks Haven Estates Limited | Households | 2023 |
| Broomwell Properties Limited | Real estate | 2016 |
| Brother Property Investment Ltd | Real estate | 2025 |
| Brow Bar Cardiff Limited | Other services | 2019 |
| Brown Investment Properties Ltd | Real estate | 2018 |
| Bruno Mani Ltd. | Professional & scientific | 2015 |
| Bruno Timber Products Ltd | Wholesale & retail | 2021 |
| Bryn Llongwr Management Company Limited | Administrative & support | 2003 |
| Bryneithin Group Ltd | Households | 2022 |
| Brynhill Golf Club Ltd | Arts & recreation | 2016 |
| BST Enterprises Limited | Financial services | 2011 |
| BT Removals Ltd | Transport & logistics | 2026 |
| Bubble & INK Ltd | Wholesale & retail | 2013 |
| Bubble Boba UK Limited | Hospitality | 2020 |
| Buildex Properties Ltd | Construction | 2020 |
| Burnett Davies Lettings Ltd | Real estate | 2021 |
| Business Boosters Limited | Information & communication | 2000 |
| Business Giraffe Investments Limited | Real estate | 2017 |
| Butetown Carnival C.I.C. | Education | 2022 |
| Butty Bach Ltd | Manufacturing | 2018 |
| Buzz Cultural CIC | Education | 2023 |
| Buzz Publishers Limited | Information & communication | 1999 |
| C & G Properties (Barry) Limited | Real estate | 2008 |
| C & M Evans Ltd | Agriculture & fishing | 2023 |
| C & S Partnerships Ltd | Hospitality | 2022 |
| C Case Carpentry Limited | Manufacturing | 2025 |
| C J Ridout Limited | Real estate | 2025 |
| C J Training and Recruitment Limited | Professional & scientific | 2015 |
| C&C Property Ltd | Real estate | 2023 |
| C&K Residential Ltd | Real estate | 2025 |
| C.Anderson (Barry) Limited | Construction | 1963 |
| C.C.S Services (Cardiff) Ltd | Administrative & support | 2015 |
| C.I.R.Z Limited | Real estate | 2024 |
| C96 Customs Ltd | Wholesale & retail | 2022 |
| Cadoc Investments Limited | Real estate | 2015 |
| Cadoxton Bowling Club Ltd. | Arts & recreation | 2020 |
| Cadoxton Carpentry Ltd | Manufacturing | 2024 |
| Cadoxton(Barry)Conservative Club & Institute Company Limited | Hospitality | 1896 |
| Caer-Taff Limited | Real estate | 2024 |
| Caesars Barry Ltd | Hospitality | 2022 |
| Caladan Enterprises Limited | Wholesale & retail | 2017 |
| Caledonian Developments (Dundee) Limited | Construction | 2018 |
| Calibre House Limited | Hospitality | 2026 |
| Calon Creations Ltd | Professional & scientific | 2025 |
| Cambrensis Garment Company Limited | Wholesale & retail | 2025 |
| Cambrian Aviation Services Ltd | Transport & logistics | 2025 |
| Cambrian Caterers (Rhoose) Ltd | Hospitality | 2015 |
| Cambrian Transport (Cambrianco) Ltd | Transport & logistics | 2010 |
| Campagne Beverages Limited | Wholesale & retail | 2024 |
| Camper Family Cymru Ltd | Wholesale & retail | 2021 |
| Canna Clinic Ltd | Health & social care | 2021 |
| Canna Consulting Limited | Administrative & support | 2016 |
| Capa Cleaning Services Limited | Administrative & support | 2023 |
| Capel Calfaria Management Limited | Real estate | 2007 |
| Capital Fabrications Limited | Manufacturing | 2024 |
| Capital Garage Equipment Limited | Manufacturing | 2019 |
| Capital Group Estates Limited | Real estate | 2020 |
| Cara Creations Ltd | Construction | 2026 |
| Cara Renovations Ltd | Real estate | 2020 |
| Caramella Properties Ltd | Real estate | 2018 |
| Cardiff & Vale Caring 4 U Limited | Health & social care | 2015 |
| Cardiff Aesthetic Clinic Ltd | Other services | 2025 |
| Cardiff Alarm Systems Ltd | Administrative & support | 2018 |
| Cardiff and Vale Citizens Advice Bureau Ltd | Information & communication | 2001 |
| Cardiff and Vale Glazing Limited | Wholesale & retail | 2021 |
| Cardiff Catering Limited | Hospitality | 2023 |
| Cardiff Fencing Limited | Construction | 2011 |
| Cardiff Junior Devils Ice Hockey Academy Limited | Education | 2020 |
| Cardiff Road Hand Car Wash Ltd | Administrative & support | 2023 |
| Cardiff Vending Limited | Hospitality | 2008 |
| Cardiff Web Development Ltd | Information & communication | 2012 |
| Cardio Core Fit Limited | Information & communication | 2025 |
| Cardio Core Fitness Ltd | Other services | 2010 |
| Care-In-Wales Ltd | Health & social care | 2010 |
| Cariad Creative Studio Ltd | Other services | 2017 |
| Carlos Pizza & Kebab Ltd | Hospitality | 2023 |
| Carpentry Contracts Limited | Construction | 2006 |
| Carpentry Joinery Building Ltd | Administrative & support | 2011 |
| Carps Cards Ltd | Wholesale & retail | 2026 |
| Cartmex Limited | Real estate | 2017 |