| Big Blue Stuff Group Ltd | Extraterritorial | 2015 |
| Big Blue Stuff Limited | Professional & scientific | 2003 |
| Big D'S & SON Cleaning & Maintenance Limited | Administrative & support | 2023 |
| Big DAD Communications World Ltd | Real estate | 2025 |
| Big Finger Productions Ltd | Administrative & support | 2010 |
| Big Fish Developments Ltd | Real estate | 2018 |
| Big Idea Property Ltd. | Real estate | 2016 |
| Big Picture Care Group Ltd | Financial services | 2023 |
| Big Tribfest UK Limited | Arts & recreation | 2022 |
| Big Tuna Moving Ltd | Transport & logistics | 2021 |
| Big Valley Store Limited | Wholesale & retail | 2025 |
| Bigbury Down Farm Limited | Real estate | 2013 |
| Bigbury Limited | Construction | 1961 |
| Biggest Little Shop Online Limited | Wholesale & retail | 2012 |
| Biggs (Offshore Survey Consultants) Limited | Professional & scientific | 1998 |
| Bigjoe Logistics Limited | Transport & logistics | 2026 |
| Bigups Signs & Graphics Ltd | Arts & recreation | 2012 |
| Bike Stuff Ltd | Wholesale & retail | 2018 |
| Bikeaway Limited | Manufacturing | 2001 |
| Bikespace Community Interest Company | Wholesale & retail | 2010 |
| Billy Dolphin Limited | Hospitality | 2018 |
| Billy Harts Quay Holdings Ltd | Financial services | 2025 |
| Billy Harts Quay Ltd | Real estate | 2025 |
| Biodiverse Solutions Limited | Manufacturing | 2025 |
| Bioshield Services Ltd | Water & waste | 2026 |
| Biovault Family Limited | Health & social care | 2013 |
| Biovault Scientific Limited | Professional & scientific | 2012 |
| Biovault Technical Limited | Health & social care | 2012 |
| Bircham Trade Suppliers Ltd | Wholesale & retail | 2018 |
| Bird's, Wildlife & Nature Limited | Administrative & support | 2022 |
| Biryani Spot Plymouth Ltd | Hospitality | 2025 |
| Bisen Technology Investment Limited | Wholesale & retail | 2015 |
| Bishnu Ltd | Hospitality | 2024 |
| Bishop & Wheeler Limited | Construction | 2006 |
| Bispo Limited | Financial services | 2023 |
| Bistro Uncle LEO Limited | Hospitality | 2024 |
| Bite the Biscuit Fiona Films Ltd | Information & communication | 2024 |
| Bitmac Limited | Professional & scientific | 2025 |
| Bizz Enterprises Limited | Real estate | 2003 |
| BJ & JJ Group Ltd | Financial services | 2022 |
| BJ & JJ Investments Ltd | Financial services | 2017 |
| BJ Maintenance Limited | Construction | 2011 |
| BJ Portfolio Limited | Real estate | 2011 |
| BJM Construction 25 Ltd | Construction | 2025 |
| BJP (Southwest) Limited | Construction | 2023 |
| BJP Stonework&Building Ltd | Construction | 2020 |
| BK Construction (SW) Ltd | Construction | 2012 |
| BKM Developments & Maintenance Ltd | Construction | 2024 |
| Black and Brass Tattoo Collective Ltd | Other services | 2021 |
| Black and Marshall Limited | Construction | 2010 |
| Black Cat Projects Limited | Information & communication | 2015 |
| Black Cat Surf Club Ltd | Hospitality | 2024 |
| Black Dog Honey Bees Ltd | Agriculture & fishing | 2020 |
| Black Ice Group Limited | Transport & logistics | 2026 |
| Blackberry Court Management Company Limited | Households | 2012 |
| Blackdown Vets Limited | Professional & scientific | 2015 |
| Blacker Holdings Ltd | Financial services | 2016 |
| Blacklerroberts Ltd | Professional & scientific | 2012 |
| Blacklock Wholefoods Limited | Wholesale & retail | 2005 |
| Blackpool Street Cars Limited | Transport & logistics | 2012 |
| Blackwells Trading Co. Ltd | Hospitality | 2024 |
| Blades Business Consulting Ltd | Transport & logistics | 1998 |
| Blades LOW Carbon Systems Ltd | Manufacturing | 2011 |
| Blagocci Ltd | Wholesale & retail | 2024 |
| Blake DAN Kelly Ltd | Wholesale & retail | 2021 |
| Blanc Management Ltd | Professional & scientific | 2024 |
| Blanconelle Ltd | Professional & scientific | 2023 |
| Blaster Master (SW) Ltd | Administrative & support | 2023 |
| Blatchford Briar Ltd | Hospitality | 2021 |
| Bleasdale Developments Limited | Construction | 2018 |
| Blec Group UK Ltd | Construction | 2014 |
| Bligh Legal Consultancy Limited | Professional & scientific | 2011 |
| Blindology Ltd | Manufacturing | 2019 |
| Bling Construction Ltd | Construction | 2015 |
| Blitz BEE Ltd | Other services | 2021 |
| Blkc Decorators Ltd | Construction | 2017 |
| Block Clean (SW) Limited | Administrative & support | 2016 |
| Block Management Training Limited | Education | 2019 |
| Blockhead Putters Ltd | Manufacturing | 2024 |
| Blockhouse Assets Limited | Real estate | 2017 |
| Blondies Ltd | Hospitality | 2019 |
| Bloom & Cradle Ltd | Wholesale & retail | 2025 |
| Bloom Creative Learning Ltd | Information & communication | 2021 |
| Bloominek Ltd | Professional & scientific | 2002 |
| Bloop Marine Crude OIL and General Merchandise Container Vessels Limited | | 1979 |
| BLS Freeholds Ltd | Real estate | 2023 |
| BLU Square Consulting Ltd | Professional & scientific | 2021 |
| Bluco Projects Ltd | Professional & scientific | 2020 |
| Blue 6 Ltd | Professional & scientific | 2007 |
| Blue AI Recruitment Ltd | Administrative & support | 2025 |
| Blue Bay Group Limited | Real estate | 2017 |
| Blue Bubble Immersive CIC | Health & social care | 2024 |
| Blue Carriers Ltd | Transport & logistics | 2018 |
| Blue Elevation Ltd | Other services | 2019 |
| Blue Environment CIC | Arts & recreation | 2008 |
| Blue GAS Heating Ltd | Construction | 2015 |
| Blue Hand Car Wash Plymouth Ltd | Administrative & support | 2023 |
| Blue Line Foods Ltd | Hospitality | 2021 |
| Blue Line Skills Academy Ltd | Education | 2026 |
| Blue Moose Developments Ltd | Real estate | 2022 |