| Bath Welcomes Refugees | Other services | 2016 |
| Baynton Williams Estate Management Limited | Real estate | 2019 |
| Baynton Williams Holdings Limited | Professional & scientific | 2022 |
| BB Payroll Ltd | Administrative & support | 2020 |
| BCE Contractors Ltd | Construction | 2021 |
| BCN (Bath) Limited | Real estate | 1983 |
| Beahive Building Developments Limited | Construction | 2021 |
| Beanddo Limited | Other services | 2018 |
| Beazer Property Management Limited | Real estate | 2021 |
| Beehyve Limited | Information & communication | 2015 |
| Belle Automotive Ltd | Transport & logistics | 2026 |
| Benedictine Properties Ltd | Real estate | 2024 |
| Bennett Boilers Limited | Manufacturing | 2005 |
| Benny Boilers Ltd | Construction | 2021 |
| Benolli Limited | Wholesale & retail | 2023 |
| Benter Consultants Limited | Professional & scientific | 2013 |
| Benzie Installations Ltd | Construction | 2015 |
| Berko Roofing Ltd | Construction | 2023 |
| Bespoke Construction and Development Ltd | Construction | 2022 |
| Bessell Investments Ltd | Real estate | 2015 |
| Better Nature Ecotherapy CIC | Health & social care | 2023 |
| Bewley Cleaning Services Limited | Administrative & support | 2017 |
| Beyouthefull Food Limited | Wholesale & retail | 2017 |
| Bhere Limited | Hospitality | 1959 |
| Big Solar Roofs Ltd | Energy | 2016 |
| Bigwoodplay.Com Ltd | Construction | 2018 |
| Bilbao Accounting Services Ltd | Professional & scientific | 2013 |
| Bilro Properties Ltd | Real estate | 2022 |
| Bimtek Limited | Professional & scientific | 2015 |
| Bini Fine Foods Limited | Manufacturing | 2016 |
| Biotec UK Ltd | Manufacturing | 2019 |
| Bishop Construction & Maintenance Ltd | Construction | 2024 |
| BJN Heating + Plumbing Ltd | Construction | 2023 |
| Black Dog Fabrication Limited | Manufacturing | 2018 |
| Black Hound Productions Ltd | Arts & recreation | 2022 |
| Blades Music Limited | Information & communication | 2014 |
| Bligh Imaging Limited | Administrative & support | 2008 |
| Blockmatch Limited | Manufacturing | 2003 |
| Blok Management Ltd | Real estate | 2017 |
| Blounthurst Limited | Professional & scientific | 1981 |
| Blue BAG Limited | Information & communication | 2000 |
| Blue Circle Solutions Ltd | Information & communication | 2019 |
| Blue Dragon Building & Landscaping Ltd | Construction | 2025 |
| Bluebell Court Management Company Limited | Households | 1997 |
| Bluefire Films Ltd | Information & communication | 2017 |
| BM & LM Property Limited | Real estate | 2019 |
| BMT Decorating Limited | Construction | 2009 |
| BN Computer Solutions Ltd | Information & communication | 2011 |
| Boatswain Joinery Limited | Construction | 2024 |
| Boden Hill Ltd | Professional & scientific | 2012 |
| Bonadie Windows Limited | Construction | 2011 |
| Boost Trade Limited | Information & communication | 2025 |
| Bouncers Leisure Limited | Arts & recreation | 1993 |
| Bourne and Bargery Ltd | Professional & scientific | 2023 |
| Boxed Fusion Ltd | Construction | 2021 |
| Boyce Millington Limited | Construction | 2000 |
| BP Joinery & Sash Windows Ltd | Construction | 2022 |
| Bradley Engineering Bath Ltd | Professional & scientific | 2024 |
| Branta Services Limited | Extraterritorial | 2023 |
| Braysdown Bespoke Joinery Ltd | Manufacturing | 2021 |
| Break Music Limited | Arts & recreation | 2024 |
| Brew & Bloom Tea Ltd | Manufacturing | 2025 |
| Brian Fear Cars Limited | Wholesale & retail | 2009 |
| Brian Morris Electrical Installations Limited | Construction | 2010 |
| Brian Nairn Associates Limited | Professional & scientific | 2012 |
| Briarwood Landscape Architecture Limited | Administrative & support | 2020 |
| Bridges Topco Limited | Construction | 2021 |
| Brierley Hill (C&P) Limited | Real estate | 2023 |
| Bright BEE Accounting Limited | Professional & scientific | 2025 |
| Brightling Solutions Ltd | Professional & scientific | 2023 |
| Brightsidebath Limited | Construction | 2024 |
| Brightsidebristol Limited | Construction | 2022 |
| Brington Engineering Limited | Professional & scientific | 2003 |
| Bristol Business Forms (Holdings) Limited | Manufacturing | 2023 |
| Bristol Music Industry Network Limited | Information & communication | 2013 |
| Bristol Property Centre Limited | Real estate | 2009 |
| Bristol Sporting Ltd | Arts & recreation | 2025 |
| Brizzle Bars Limited | Professional & scientific | 2013 |
| Broadies Tea Limited | Wholesale & retail | 2023 |
| Broadway Freehold Investments Ltd | Administrative & support | 2018 |
| Broadway Property Investments Limited | Real estate | 1993 |
| Brooklin Models Limited | Manufacturing | 2015 |
| Brown Jenkinson (Chartering) Limited | Transport & logistics | 1998 |
| Brown Jenkinson Ltd | Transport & logistics | 2018 |
| Brown’S Roofing Ltd | Construction | 2022 |
| Brunel Media (UK) Limited | Professional & scientific | 2002 |
| Brunel Training Solutions Ltd | Professional & scientific | 2013 |
| Bryant's South West Fabrications Limited | Professional & scientific | 2023 |
| BSF Construction Ltd | Construction | 2026 |
| BT Leisure Ltd | Arts & recreation | 2022 |
| Buffalo Zoomedia Limited | Information & communication | 2012 |
| Bull Terrier Limited | Arts & recreation | 2012 |
| Burdens Properties Ltd | Real estate | 2022 |
| Butterell Barton Limited | Real estate | 2017 |
| Butterell Consulting Ltd | Professional & scientific | 2019 |
| BW Construction and Landscaping Ltd | Administrative & support | 2020 |
| BW Electrical (South West) Ltd | Construction | 2017 |
| C & S Cleaning Services (Radstock) Ltd | Administrative & support | 2011 |
| C & S Davis Ltd | Real estate | 2019 |
| C and N Commercials Limited | Transport & logistics | 2002 |