| Baltic Football Ltd | Wholesale & retail | 2021 |
| Baltic Salmon Project Ltd | Agriculture & fishing | 2018 |
| Baltic Wave OU Ltd | Wholesale & retail | 2012 |
| Balumi Ltd | Wholesale & retail | 2025 |
| Balwant Anand Ltd | Wholesale & retail | 2022 |
| BAM 2 Limited | Real estate | 2022 |
| BAM Apartments Limited | Real estate | 2018 |
| BAM Property Holdings Ltd | Construction | 2026 |
| Bamba Promotions Limited | Arts & recreation | 2019 |
| Bambinibande Ltd | Other services | 2025 |
| Bamboo Delicious Limited | Hospitality | 2025 |
| Bamboo Removals & Storage CYF | Transport & logistics | 2024 |
| Bamboo Shift Ltd | Health & social care | 2017 |
| Bamboo Studio Group Ltd | Administrative & support | 2017 |
| Bamboo Web Design Ltd | Information & communication | 2021 |
| Bambridge Gallery Limited | Administrative & support | 2020 |
| Bampag Real Estate Limited | Real estate | 2021 |
| Banana Badger Ltd | Professional & scientific | 2022 |
| Banasla Solutions Ltd | Administrative & support | 2022 |
| Banc DU Energy Park Limited | Energy | 2020 |
| Bandalover Limited | Wholesale & retail | 2026 |
| Bandiau Pres Cymru - Brass Bands Wales Limited | Professional & scientific | 2021 |
| Baneswell Ltd | Real estate | 2017 |
| Banfield Equestrian Ltd | Agriculture & fishing | 2018 |
| Banfields Building Services Consultancy Limited | Professional & scientific | 2011 |
| Bang Post Production Limited | Information & communication | 2006 |
| Bangkok Cafe 2022 Limited | Hospitality | 2022 |
| Bangladesh Welfare Association Cardiff | Other services | 2012 |
| Bangs and Sons Limited | Other services | 2020 |
| Banharie Limited | Administrative & support | 2022 |
| Banif Factoring Ltd | Financial services | 2021 |
| Banjo Court Management Co. Ltd | Households | 2019 |
| Banjum Travel Agency Ltd | Administrative & support | 2024 |
| Bank View (Kingswood) Management Company Limited | Households | 2007 |
| Bankside Associates Ltd | Administrative & support | 2017 |
| Banksysbrickwork Limited | Construction | 2025 |
| Bann Sakunee Ltd | Health & social care | 2017 |
| Bannau Limited | Professional & scientific | 2011 |
| Banner Block Management Ltd | Real estate | 2024 |
| Bannon Healthcare Limited | Health & social care | 2018 |
| Bano Goods Limited | Wholesale & retail | 2021 |
| Banova Ltd | Wholesale & retail | 2026 |
| Banquetra Expo Ltd | Hospitality | 2026 |
| Bansero Services Ltd | Administrative & support | 2021 |
| Bant a LA Cart Limited | Wholesale & retail | 2003 |
| Bantu Restaurants Limited | Hospitality | 2022 |
| BAO FU Limited | Hospitality | 2026 |
| BAO Selecta Ltd | Hospitality | 2024 |
| Baobab Solution Limited | Other services | 2019 |
| Baobit Ltd | Financial services | 2021 |
| Baota Ltd | Wholesale & retail | 2022 |
| Baoweida UK Limited | Transport & logistics | 2026 |
| Baoxiaoshi Ltd | Hospitality | 2023 |
| Baoxiong LI Ltd | Manufacturing | 2021 |
| Baoyu Foreign Trade Ltd | Wholesale & retail | 2025 |
| Bapm Limited | Construction | 2008 |
| Baptiste’S Grenada Herbals Ltd | Wholesale & retail | 2026 |
| Bar 105 Ltd | Hospitality | 2018 |
| Bar 44 (Cardiff) Limited | Hospitality | 2013 |
| Bar 44 (Clifton) Limited | Hospitality | 2018 |
| Bar 44 (Tapas Y Copas) Limited | Hospitality | 2012 |
| Bar 44 Limited | Hospitality | 2009 |
| Bar Band Explorer Ltd | Information & communication | 2020 |
| Bara Intol Limited | Professional & scientific | 2010 |
| Baraca Home Ltd | Wholesale & retail | 2024 |
| Baraka ORO Gold Ltd | Wholesale & retail | 2025 |
| Barakabrands Ltd | Wholesale & retail | 2025 |
| Baran Barbers Ltd | Other services | 2019 |
| Baraqa Ltd | Wholesale & retail | 2024 |
| Baravin Limited | Hospitality | 2004 |
| Barbarian Cosmetics Limited | Wholesale & retail | 2021 |
| Barbarian Fitness Ltd | Extraterritorial | 2021 |
| Barber 12 Limited | Other services | 2024 |
| Barber Boys Club Ltd | Other services | 2017 |
| Barber Holdings Limited | Professional & scientific | 2005 |
| Barber Jeff Ltd | Other services | 2025 |
| Barber Trading Limited | Professional & scientific | 2015 |
| Barbering School Wales Limited | Education | 2021 |
| Barbers&Salons Ltd | Other services | 2017 |
| Barbican Demolition Ltd | Construction | 2020 |
| Barbican ISA Limited | Financial services | 2018 |
| Barbrook Close Management Company Limited | Households | 1986 |
| Barbury Services Ltd | Health & social care | 2024 |
| Barchester Wales Limited | Health & social care | 2022 |
| Barclay Devere Ltd | Hospitality | 2023 |
| Barclay OIL Services Ltd | Mining & quarrying | 2011 |
| Barclay Richmond Associates Ltd | Administrative & support | 2025 |
| Barclays Metal World Limited | Wholesale & retail | 2019 |
| Barcode Brighton Ltd | Hospitality | 2019 |
| Barcud IT Services Ltd | Information & communication | 2012 |
| Barcud Shared Services Limited | Professional & scientific | 2019 |
| Bard's Tales RUM Ltd | Wholesale & retail | 2024 |
| Bardes UK. Ltd | Wholesale & retail | 2021 |
| Bardsey Property Developments Limited | Construction | 2018 |
| Barek Ltd | Information & communication | 2016 |
| Barford Owen Davies Limited | Professional & scientific | 2016 |
| Bargain Foods Dudley Limited | Wholesale & retail | 2019 |
| Bargain Motors Cardiff Ltd | Wholesale & retail | 2026 |
| Bargane Import & Export Limited | Information & communication | 2014 |
| Bargeat Limited | Wholesale & retail | 2025 |