| Jessica's Farmhouse Bakery Ltd | Manufacturing | 2022 |
| Jewels Care @ Home Ltd | Health & social care | 2020 |
| Jeztek Limited | Information & communication | 2008 |
| JG Technologies Limited | Administrative & support | 1999 |
| JHL Rees Enterprises Limited | Arts & recreation | 2012 |
| JIM Blake Project Management Consultancy Ltd | Professional & scientific | 2025 |
| JJ Heating Limited | Construction | 2022 |
| Jjdk Ltd | Agriculture & fishing | 2026 |
| JLH Health & Safety Consultant and Trainer Limited | Professional & scientific | 2025 |
| JMB Legal Services Limited | Administrative & support | 2013 |
| JMH Dorset Limited | Wholesale & retail | 2016 |
| JMK Autos Limited | Wholesale & retail | 2013 |
| Jobson's Fire and Chimney Centre Limited | Administrative & support | 2025 |
| JOE Newton Electrical Ltd | Construction | 2020 |
| John Arthur SCS Limited | Professional & scientific | 2011 |
| John Booth Consultancy Ltd | Construction | 2015 |
| John Marquis Ltd | Administrative & support | 2006 |
| John Penfold & Daughter Limited | Wholesale & retail | 2024 |
| John Roberts Limited | Construction | 2004 |
| Johnson & Kirby Limited | Hospitality | 1973 |
| Johnstone Court Management Company Number 2 Limited | Households | 1993 |
| Jolliffes Global Consultancy Ltd | Professional & scientific | 2024 |
| JON Ashley Wood Ltd | Hospitality | 2025 |
| Jordan & Faber Investments Limited | Construction | 2020 |
| Jordan & Faber Limited | Construction | 2002 |
| Jordan Construction Southern Limited | Construction | 2015 |
| Joslin Court Management Company Limited | Households | 2003 |
| Joys Enterprises Limited | Wholesale & retail | 2022 |
| JPF Plumbing Heating & GAS Limited | Construction | 2014 |
| JPF Renewables Limited | Construction | 2023 |
| JPS Solutions Ltd | Professional & scientific | 2024 |
| JS Carpentry, Roofing and Leadwork Limited | Construction | 2025 |
| JSC Chiropractic Ltd | Health & social care | 2013 |
| JSP Solutions Ltd. | Hospitality | 2014 |
| JSR Property Holdings Ltd | Real estate | 2019 |
| JT Innovations Limited | Manufacturing | 2011 |
| JT Resolutions Limited | Professional & scientific | 2019 |
| JTW Maintenance Limited | Construction | 2024 |
| Jubilee Court (Poundbury) Management Limited | Households | 2007 |
| Jubilee Way RTM Company Limited | Administrative & support | 2015 |
| Jude Norman Properties Limited | Real estate | 2022 |
| Jurassic Apartments Limited | Hospitality | 2023 |
| Jurassic Aqua Sports LLP | | 2019 |
| Jurassic Bay Holidays Ltd | Hospitality | 2016 |
| Jurassic Clean Solutions Ltd. | Administrative & support | 2024 |
| Jurassic Coast Building and Maintenance Ltd | Construction | 2021 |
| Jurassic Coast Competitions Limited | Other services | 2023 |
| Jurassic Coast Defenders Ltd | Wholesale & retail | 2024 |
| Jurassic Coast Holiday Apartments Ltd | Hospitality | 2010 |
| Jurassic Coast Pest Control Ltd. | Administrative & support | 2014 |
| Jurassic Coast Pizzas Limited | Hospitality | 2019 |
| Jurassic Consulting Ltd | Information & communication | 2021 |
| Jurassic Diggerworks Limited Partnership | | 2022 |
| Jurassic Freedom Retailing Limited | Wholesale & retail | 2022 |
| Jurassic Gymnastics Ltd | Education | 2025 |
| Jurassic Home Improvements Ltd | Construction | 2020 |
| Jurassic House Clearance Company Limited | Water & waste | 2025 |
| Jurassic Ices Ltd | Hospitality | 2025 |
| Jurassic Jetski Tours Limited | Arts & recreation | 2015 |
| Jurassic Pirate Ltd | Wholesale & retail | 2024 |
| Jurassic Property Services Ltd | Real estate | 2025 |
| Jurassic Rocks Limited | Arts & recreation | 2015 |
| Just Keeping Busy Ltd | Manufacturing | 2025 |
| Just Racing (UK) Ltd | Arts & recreation | 2005 |
| Justmc Ltd | Arts & recreation | 2020 |
| K & D Developments Dorset Limited | Construction | 2021 |
| K N L (Services) Limited | Construction | 2013 |
| Kahvoo Ltd | Manufacturing | 2025 |
| Kanya's Kitchen Ltd | Hospitality | 2021 |
| Karls Carpets & Flooring Limited | Wholesale & retail | 2020 |
| Karser Holdings Limited | Real estate | 2005 |
| Kateryna Beauty Ltd | Other services | 2022 |
| KB Thermo Ltd | Construction | 2026 |
| Kbfs Financial Limited | Professional & scientific | 2017 |
| KBR Electrical Ltd | Construction | 2022 |
| Keates Adventures Ltd | Manufacturing | 2018 |
| Keith Haines Limited | Professional & scientific | 1994 |
| Keith Starr Services Ltd | Manufacturing | 2007 |
| Kelly Parker Medicolegal Midwifery Experts Limited | Professional & scientific | 2025 |
| Kelso Associates Ltd | Information & communication | 2016 |
| Kelt Group Ltd | Real estate | 2018 |
| Kempston House Residents Association Limited | Households | 1988 |
| Kendor Limited | Real estate | 2016 |
| Kennedy Legg Limited | Professional & scientific | 2003 |
| Kennedys Estate Agents Limited | Real estate | 2008 |
| Kennedy`S Bodyshop Limited | Wholesale & retail | 2006 |
| Kestrel Managed Solutions Limited | Information & communication | 2017 |
| Keyson Rental Services Ltd | Other services | 2011 |
| Kika Beach Limited | Hospitality | 2002 |
| Kikirae Ltd | Information & communication | 2025 |
| Kildare Court (Weymouth) Limited | Households | 2005 |
| Killgarren Limited | Households | 2002 |
| King Barrow Management Co Ltd | Households | 2021 |
| King of Hearts (Weymouth) Limited | Wholesale & retail | 2021 |
| Kings (Weymouth) Limited | Hospitality | 1979 |
| Kingstons Weymouth Limited | Manufacturing | 2012 |
| Kinroc Limited | Real estate | 2023 |
| Kinroc Scaffolding Limited | Construction | 2024 |
| Kirmussaudio (Europe) Limited | Other services | 2018 |
| KIT Roofing Limited | Construction | 2026 |