| Biggrin Ltd | Health & social care | 2019 |
| Biggswood Limited | Information & communication | 2012 |
| Bike Cornwall | Arts & recreation | 2008 |
| Bilkey and Bray Limited | Energy | 2012 |
| Bill-E-Buddy Limited | Information & communication | 2025 |
| Binc Ltd | Real estate | 2016 |
| Birch Tree Interiors Limited | Manufacturing | 2026 |
| Birch Tree Marine Limited | Construction | 2020 |
| Bird Box Music CIC | Education | 2025 |
| Birdhouse Company Lets Ltd | Households | 2025 |
| Bispham Construction Ltd | Construction | 2021 |
| Bittern Estates Management Company Limited | Households | 2005 |
| Bizbraz Services Ltd | Wholesale & retail | 2025 |
| Bizwize Ltd | Professional & scientific | 2025 |
| BJA Developments Ltd | Construction | 2020 |
| BKM Stores Limited | Wholesale & retail | 2025 |
| Black Cat Evolution Ltd | Information & communication | 2006 |
| Black Letter Law Ltd | Professional & scientific | 2021 |
| Black Star Strength Ltd | Other services | 2018 |
| Blackberry Lane Kilkhampton Management Co Limited | Households | 2022 |
| Blackberry Renovations Ltd | Real estate | 2019 |
| Blackstuff Associates Ltd | Professional & scientific | 2023 |
| Blagdon Water Gardens Project Limited | Construction | 2019 |
| Blake Beaux Limited | Other services | 2021 |
| Blazey Limited | Financial services | 2024 |
| Bleed Control (UK) Ltd | Wholesale & retail | 2024 |
| Blenkin Building Ltd | Administrative & support | 2014 |
| Blewett's Holdings Limited | Financial services | 2021 |
| Blincoe Limited | Health & social care | 2023 |
| Bliss Hair Design (Truro) Limited | Other services | 2014 |
| Bloc Leisure Ltd | Construction | 2022 |
| Bloody Mary Metal Jewellery Ltd | Manufacturing | 2022 |
| Bloom AI Ltd | Information & communication | 2025 |
| Blowinghouse Limited | Real estate | 2009 |
| Blue 5 (SW) Ltd | Real estate | 2020 |
| Blue Apple Boats LLP | | 2023 |
| Blue Boat Trading LLP | | 2026 |
| Blue Chip Homes (UK) Limited | Real estate | 2012 |
| Blue Cornwall Limited | Hospitality | 2002 |
| Blue DOT Games Limited | Information & communication | 2023 |
| Blue FIN Yachts Ltd | Manufacturing | 2006 |
| Blue Mustard (Truro) Limited | Extraterritorial | 2005 |
| Blue Planet Images Co. Limited | Professional & scientific | 2000 |
| Blue Planet Photos Co. Limited | Professional & scientific | 2000 |
| Blue Screen IT Limited | Information & communication | 2004 |
| Blue Seas Education Limited | Education | 2017 |
| Blue Wing Gallery Limited | Wholesale & retail | 1999 |
| Bluebell Connections Ltd | Wholesale & retail | 2018 |
| Bluekind Limited | Administrative & support | 2026 |
| Blueshore Holdings Limited | Financial services | 2025 |
| Bluewater Lettings Ltd | Real estate | 2019 |
| BLW Contracting Ltd | Construction | 2025 |
| BM Engineering Services Ltd | Professional & scientific | 2022 |
| Bnet Integrated Solutions Ltd | Information & communication | 2026 |
| BNG Cornwall Ltd | Real estate | 2026 |
| Boadman Limited | Information & communication | 2026 |
| Boaz Studio Limited | Professional & scientific | 2015 |
| Boba Skellington Ltd | Wholesale & retail | 2020 |
| Bodinnick Consultancy Partners Limited | Professional & scientific | 2015 |
| Body Bounce Newquay Ltd | Arts & recreation | 2025 |
| Bodypharm Limited | Wholesale & retail | 2003 |
| BOE Scaffolding Ltd | Construction | 2025 |
| Bohella Bars Limited | Hospitality | 2016 |
| Boho 18 Limited | Hospitality | 2025 |
| Bolster Training Ltd | Other services | 2024 |
| Bond Lloyd Consulting Ltd | Professional & scientific | 2016 |
| Bondso Ltd | Administrative & support | 2006 |
| Bone & Joint Solutions LLP | | 2005 |
| Bonython House Management Company Limited | Households | 2007 |
| Book Enigma Ltd | Administrative & support | 2022 |
| Boot UP! CIC | Education | 2014 |
| Borgia Bull Catering Ltd | Hospitality | 2022 |
| Boringdon Hall Plympton Limited | Hospitality | 2010 |
| Boscolleth Gardens Property Management Company Limited | Households | 2020 |
| Boscrege Caravan Sales Limited | Wholesale & retail | 2018 |
| Bostock Property and Letting Ltd | Real estate | 2023 |
| Boswiddle Water Management Company Limited | Water & waste | 2014 |
| Boswin 2015 Limited | Real estate | 2015 |
| Botanical Medicine Research Collaborative Limited | Professional & scientific | 2026 |
| Botched Ltd | Manufacturing | 2023 |
| Botreaux Management Company Limited | Households | 1987 |
| Botus Consultants Limited | Professional & scientific | 2020 |
| Bouldens Garden Ltd | Real estate | 2020 |
| Bouldens Orchard Management Company Limited | Households | 2021 |
| Bournemouth Educational Centre Limited | Education | 1992 |
| Bowgie Inn Limited | Hospitality | 2008 |
| Boxxy Games Ltd | Information & communication | 2026 |
| BPH Investments Ltd | Real estate | 2026 |
| Braithwaite Associates (UK) Limited | Professional & scientific | 2012 |
| Branch Richards Ltd | Construction | 2014 |
| Branded Matches Ltd | Professional & scientific | 2020 |
| Brands ET AL Ltd | Professional & scientific | 2016 |
| Breakers Beach Cafe Ltd | Hospitality | 2018 |
| Breakwater Pentire Management Company Limited | Households | 2020 |
| Breathing Buddy Ltd | Professional & scientific | 2016 |
| Brian P Keast & Sons Ltd | Construction | 2005 |
| Bridging the GAP Familytech Ltd | Information & communication | 2026 |
| Brighton Terrace Management Co. Ltd | Real estate | 2021 |
| Brihur Ltd | Construction | 2025 |
| Britanic Industries Limited | Hospitality | 1985 |