| BH6 Books and Home Ltd | Wholesale & retail | 2017 |
| BH8 Care Ltd | Health & social care | 2024 |
| BH9 One Limited | Real estate | 2017 |
| Bhaanu Ltd | Wholesale & retail | 2023 |
| Bhappy Ltd | Health & social care | 2022 |
| BHD 2014 Limited | Real estate | 2014 |
| BHD School Transport Ltd | Transport & logistics | 2023 |
| Bhgas South Limited | Construction | 2026 |
| BHL Software Solutions Ltd | Other services | 2022 |
| Bhmn Limited | Hospitality | 2024 |
| Bhty Cleaning Limited | Administrative & support | 2025 |
| BHX Movie Ltd | Information & communication | 2022 |
| BHX TCG Ltd | Manufacturing | 2026 |
| Bica Bakery Ltd | Hospitality | 2025 |
| Bickerley Garage Ringwood Limited | Wholesale & retail | 2016 |
| Bicknells Consultants Ltd | Information & communication | 2012 |
| Biddle Property Management Limited | Real estate | 2024 |
| Big App Consultancy Limited | Information & communication | 2011 |
| Big Bear Crafting Ltd | Wholesale & retail | 2026 |
| Big Bear Photography Limited | Professional & scientific | 2013 |
| Big Beaver Limited | Extraterritorial | 1997 |
| Big Knowledge Consultancy and Management Ltd | Professional & scientific | 2018 |
| Big Smart Quiz Limited | Administrative & support | 2026 |
| Big T Management Ltd | Professional & scientific | 2021 |
| Big TL Properties Ltd | Real estate | 2024 |
| Biggs Heat Technologies Ltd | Construction | 2015 |
| Bigtime Ltd | Financial services | 2026 |
| Bigwigs Bakery Ltd | Hospitality | 2019 |
| Bike Race Hub C.I.C. | Information & communication | 2024 |
| Bikram Yoga Bournemouth Limited | Health & social care | 2011 |
| Bilingual Finances Ltd | Financial services | 2017 |
| Bill Agency Ltd | Professional & scientific | 2019 |
| Bill Giles Fencing Ltd | Other services | 2026 |
| Bill Smart Communications Ltd | Information & communication | 2018 |
| Bill Smart Energy Ltd | Energy | 2024 |
| Bill Smart Home Emergency Ltd | Other services | 2019 |
| Bill Smart Ltd | Wholesale & retail | 2022 |
| Bill Smart Motor Club Ltd | Wholesale & retail | 2018 |
| Billib Sales (U.K.) Limited | Wholesale & retail | 1973 |
| Billy Bones Limited | Construction | 2017 |
| Billy Bones Lodgings Ltd | Hospitality | 2021 |
| BIN Care Limited | Administrative & support | 2019 |
| Bingo Holdings Ltd | Financial services | 2022 |
| Bingostars Limited | Information & communication | 2025 |
| BIO E Sano Limited | Hospitality | 2015 |
| Bio-Kil Ltd | Construction | 2016 |
| Biolabshop Limited | Wholesale & retail | 2022 |
| Biolshopbiol Ltd | Wholesale & retail | 2026 |
| Biopurus Ltd | Wholesale & retail | 2015 |
| Biosecurity Solutions Limited | Wholesale & retail | 2020 |
| Birch and Oak Ltd | Wholesale & retail | 2025 |
| Birchclaim Limited | Construction | 1991 |
| Birchmile Ltd | Construction | 2025 |
| Birchmore Building Services Limited | Construction | 2007 |
| Birchpool Limited | Financial services | 2025 |
| Birchwood Court Limited | Households | 2000 |
| Bird Wellbeing Ltd | Manufacturing | 2025 |
| Birds EYE Marketing Limited | Professional & scientific | 2017 |
| Birds Hill Nursing Home Limited | Extraterritorial | 2016 |
| Birth-Ease Ltd | Wholesale & retail | 2007 |
| Bishop Properties Dorset Ltd | Real estate | 2025 |
| Bishopsgate Ventures Limited | Real estate | 1996 |
| Bison Property Management Ltd | Real estate | 2017 |
| Bisterne Developments Limited | Construction | 1994 |
| Bisterne Farms | Agriculture & fishing | 1980 |
| Bisterne Farms Holdings Limited | Financial services | 2016 |
| Bitguard Ltd | Administrative & support | 2022 |
| Biula Cares Limited | Health & social care | 2025 |
| Bizibees Limited | Extraterritorial | 2002 |
| Bizisc Ltd | Wholesale & retail | 2026 |
| Biznov Limited | Wholesale & retail | 2017 |
| Bizpedia UK Limited | Administrative & support | 2013 |
| BJ Hall Ltd | Wholesale & retail | 2008 |
| BJC Carpentry and Building Ltd | Construction | 2024 |
| BJM Technology Limited | Professional & scientific | 2012 |
| BKB Accountants (Bournemouth) Ltd | Professional & scientific | 2025 |
| BKH & SON Decorating Services Ltd | Construction | 2013 |
| BKM Consulting Coaching Publishing Ltd | Other services | 2026 |
| BKM Plus Ltd | Real estate | 2021 |
| BKM Wellbeing Solutions Ltd | Other services | 2015 |
| BKR Couriers Limited | Transport & logistics | 2013 |
| Black & Gold London Ltd | Professional & scientific | 2026 |
| Black & White Ventures Limited | Real estate | 2007 |
| Black and Forest Properties Ltd | Real estate | 2025 |
| Black Box Collective Ltd | Other services | 2024 |
| Black Carers and Care Workers Network (BCP and Dorset) CIC | Health & social care | 2025 |
| Black Cat Estates Limited | Real estate | 2020 |
| Black INK Brew Ltd | Wholesale & retail | 2021 |
| Black Knight Football Club UK Limited | Financial services | 2022 |
| Black Knight Stadium Limited | Real estate | 2025 |
| Black Light Studio Ltd | Transport & logistics | 2021 |
| Black Petal Ltd | Health & social care | 2025 |
| Black Waxx Limited | Information & communication | 2025 |
| Blackboxit Limited | Information & communication | 2005 |
| Blackgate Services Ltd | Information & communication | 2015 |
| Blackjack Ltd | Manufacturing | 2015 |
| Blacklane Developments Limited | Construction | 2017 |
| Blackmagic Design (Technology) Limited | Information & communication | 2011 |
| Blackpoll Holdings Limited | Financial services | 2021 |
| Blackridge Tech Ltd | Information & communication | 2025 |