| JL Plastering & SON Ltd | Construction | 2014 |
| JLB Advisory Ltd | Professional & scientific | 2023 |
| JMH Assemblies Ltd | Wholesale & retail | 2020 |
| JMI Bathrooms Limited | Wholesale & retail | 2001 |
| JOE Norledge Limited | Information & communication | 2025 |
| JOE Tucker Fitness Limited | Arts & recreation | 2013 |
| John Martin Coaches Ltd | Transport & logistics | 2002 |
| John Scott Builders (Somerset) Limited | Construction | 1998 |
| John Wainwright & Co. Limited | Mining & quarrying | 1902 |
| John Wainwright Systems Limited | Manufacturing | 1995 |
| Joinerysoft Limited | Information & communication | 2006 |
| Jokers Bouncy Castles Limited | Arts & recreation | 2025 |
| Jolene & Co. Ltd | Other services | 2011 |
| Jolly Jumpers South West Ltd | Arts & recreation | 2023 |
| Jolly Living Limited | Real estate | 2020 |
| JON Taylor Dairy Ltd | Wholesale & retail | 2004 |
| Jonny’S INK Ltd | Arts & recreation | 2022 |
| Joramax Ltd | Construction | 2023 |
| Jordan Systems Limited | Information & communication | 2012 |
| Josie Mitchell Jewellery Ltd | Manufacturing | 2024 |
| Jpconservation Limited | Construction | 2024 |
| JRS Aggregates Limited | Wholesale & retail | 2024 |
| JRT Decorating Limited | Construction | 2019 |
| JS Driving Service Ltd | Transport & logistics | 2019 |
| JSW Landscaping and Surfacing Ltd | Administrative & support | 2018 |
| Jubilee Terrace Ltd | Households | 2004 |
| Jump Start Therapy CIC | Arts & recreation | 2023 |
| Just Roll With IT Limited | Construction | 2017 |
| Justdrewsound Ltd | Information & communication | 2022 |
| JW Waste Recycling Limited | Water & waste | 2009 |
| K & S Liquid Screed Ltd | Construction | 2016 |
| K a Parsons Limited | Hospitality | 2015 |
| K.M. Steel Fabrications Limited | Manufacturing | 1997 |
| Kabuki Limited | Other services | 2021 |
| KAJ Care Ltd | Health & social care | 2019 |
| Kapunda Properties Limited | Real estate | 1963 |
| Katchaloureg Limited | Real estate | 2020 |
| Kate Hill Chauffeur Hire Limited | Transport & logistics | 2011 |
| Kathan Ltd | Real estate | 2007 |
| Katie Primrose Ltd | Professional & scientific | 2025 |
| Keenpine Limited | Wholesale & retail | 2000 |
| Kellala Consulting Ltd | Information & communication | 2026 |
| Kelly Scott Ltd | Financial services | 2010 |
| Kemish Engineering Designs Ltd | Manufacturing | 2020 |
| Kempthorne Construction Services Ltd | Construction | 2024 |
| Kent Medical Services Limited | Professional & scientific | 2021 |
| Keywood Estates Ltd | Real estate | 2006 |
| KH Transformation Services Ltd | Professional & scientific | 2026 |
| Kilburn Contractors Limited | Construction | 2017 |
| Killens Limited Liability Partnership | | 2008 |
| Kilmersdon Limited | Professional & scientific | 2023 |
| Kilmory Investments Limited | Real estate | 2016 |
| King Farm Plastic Recycling Ltd | Manufacturing | 2019 |
| King Watkins Limited | Professional & scientific | 2003 |
| Kings Mews Car Park Management Company Limited | Households | 2021 |
| Kings Oak Accountancy (Somerset) Ltd | Professional & scientific | 2015 |
| Kings Oak Elevate Limited | Administrative & support | 2025 |
| Kingston Road Property Management Limited | Households | 2024 |
| Kipling Build Limited | Construction | 2024 |
| Kipling Contracts UK Limited | Construction | 2010 |
| Kipling Invest Limited | Construction | 2024 |
| Kiss Management Ltd | Administrative & support | 2017 |
| KIT Works Ltd | Information & communication | 2025 |
| Kitenzo Ltd | Information & communication | 2024 |
| Klouter.Ai Limited | Information & communication | 2024 |
| KMB Crates Ltd | Manufacturing | 2025 |
| Knights Plumbing and Property Renovations Ltd | Construction | 2021 |
| Krug Developments Limited | Construction | 2019 |
| KSB Holistic & Support Solutions Ltd | Administrative & support | 2025 |
| Kurve Installation Group Ltd | Construction | 2021 |
| KWM Motors Ltd | Wholesale & retail | 2022 |
| KY Retails Ltd | Wholesale & retail | 2021 |
| L Cole Construction Ltd | Construction | 2024 |
| L J Property Developments Limited | Construction | 2011 |
| L&B Herbert Ltd | Professional & scientific | 2023 |
| L&J Renovations Ltd | Construction | 2023 |
| Lakeside Contracting Limited | Other services | 2007 |
| Laminar Limited | Extraterritorial | 2019 |
| Laminar Pumps Limited | Professional & scientific | 2016 |
| Landex (Properties) Limited | Manufacturing | 1984 |
| Lane Brothers Construction Limited | Construction | 2018 |
| Lane Brothers Developments Ltd | Real estate | 2021 |
| Laparoscopique Limited | Health & social care | 2019 |
| Lapn Holdings Ltd | Construction | 2021 |
| Lara & Pinto Limited | Hospitality | 2015 |
| Larchwood Court (Radstock) Management Company Limited | Households | 2002 |
| Lathbury Limited | Professional & scientific | 2012 |
| Lawrence Education International Limited | Education | 2015 |
| Lawrence Goodridge Motor Repairs Limited | Wholesale & retail | 2015 |
| Lazy Days Landscaping Ltd | Administrative & support | 2013 |
| LCI Spraybooths Ltd | Manufacturing | 2015 |
| LCJ Food Ltd | Manufacturing | 2024 |
| Leadership Trainer Ltd | Professional & scientific | 2010 |
| Legalkeepers Limited | Professional & scientific | 2025 |
| Leia Jewellery Ltd | Wholesale & retail | 2024 |
| Lemonbay Limited | Real estate | 1999 |
| Lenihan Developments Limited | Construction | 2007 |
| Letran Ltd | Wholesale & retail | 2020 |
| Lewis Maintenance Group Ltd | Manufacturing | 2019 |
| Libra Skincare Ltd | Wholesale & retail | 2015 |