| J&L Property Specialists Ltd | Real estate | 2025 |
| J&T Houses Limited | Real estate | 2017 |
| J&T Plumbing & Heating Specialists Ltd | Construction | 2015 |
| J.M.F.B Ltd | Manufacturing | 2025 |
| J3 Interiors Ltd | Manufacturing | 2019 |
| J3 Projects Ltd | Professional & scientific | 2026 |
| Jacob and Sons Accommodation Ltd | Real estate | 2016 |
| Jacobs Stevens Roofing Ltd | Construction | 2022 |
| Jaivik Limited | Hospitality | 2024 |
| James Jewellers Bognor Ltd | Wholesale & retail | 2016 |
| Jamesmunro Limited | Other services | 2021 |
| Jammsy Limited | Wholesale & retail | 2025 |
| Jasmine Taste Ltd | Hospitality | 2025 |
| Java Vibes Limited | Hospitality | 2018 |
| Jaxon Consulting Ltd | Professional & scientific | 2016 |
| JAY1 Maintenance Ltd | Construction | 2023 |
| Jbcomposites Ltd | Manufacturing | 2021 |
| JC Crockford Holdings Ltd | Financial services | 2026 |
| JC Homes Limited | Real estate | 2023 |
| JC Properties Southern Limited | Real estate | 2022 |
| JC Spiers Limited | Construction | 2015 |
| JC Tyres Ltd | Wholesale & retail | 2022 |
| JCM Couriers Ltd | Transport & logistics | 2019 |
| Jcomp Limited | Manufacturing | 2016 |
| JD General House Work Ltd | Construction | 2018 |
| JDJ Inns Limited | Hospitality | 2017 |
| Jefferson Court Management Company Limited | Households | 1984 |
| Jelink Trading Limited | Wholesale & retail | 2025 |
| Jemcast Limited | Professional & scientific | 2017 |
| Jemiclad Limited | Construction | 2017 |
| Jeneses Property Limited | Real estate | 2019 |
| Jerk Flavaz Ltd. | Hospitality | 2023 |
| Jet-Eng Ltd | Professional & scientific | 2016 |
| Jevington Court Leaseholders Limited | Households | 1992 |
| JEZ Mobile Valeting Limited | Administrative & support | 2020 |
| JGB Building Services Limited | Construction | 2013 |
| JH Hammond Contractors Limited | Construction | 2007 |
| Jhbuilds Ltd | Construction | 2026 |
| JHG Vehicle Services Ltd | Wholesale & retail | 2023 |
| Jishlitrendora Ltd | Wholesale & retail | 2025 |
| JJ PUB Operator UK Ltd | Hospitality | 2023 |
| JJB Leisure Limited | Hospitality | 2024 |
| JJC Southern Flooring Limited | Construction | 2021 |
| JJR Designs Limited | Professional & scientific | 2006 |
| Jjsn Limited | Information & communication | 2016 |
| JLF Composites Ltd | Professional & scientific | 2025 |
| Jlgworks Ltd | Professional & scientific | 2024 |
| JLK Recruitment Ltd | Administrative & support | 2023 |
| JLO Initiatives Ltd | Administrative & support | 2025 |
| JM Servicing and Maintenance Ltd | Professional & scientific | 2025 |
| JMG Props Limited | Administrative & support | 2014 |
| JMG Roofing Services Ltd | Construction | 2023 |
| Jmletvest Ltd | Real estate | 2025 |
| JMS Deployments Ltd | Administrative & support | 2022 |
| Joanne's Shoes Limited | Wholesale & retail | 2015 |
| Jodybell Ltd | Hospitality | 2024 |
| Joe's Cocktail Bar Limited | Hospitality | 2025 |
| John Antill Ltd | Information & communication | 2012 |
| John Hall Consulting Ltd. | Professional & scientific | 2017 |
| John Lawman Associates Limited | Professional & scientific | 2012 |
| John Wiley & Sons Limited | Information & communication | 1959 |
| Johnston and Cowley Ltd | Wholesale & retail | 1999 |
| Jonah's Mead Ltd | Wholesale & retail | 2021 |
| Jonas Fast Solutions Limited | Construction | 2025 |
| Jonny's ALL Day Dining Ltd | Hospitality | 2018 |
| Jonny's ALL Day Property Limited | Real estate | 2025 |
| Jopate Estates Limited | Real estate | 1947 |
| Joyinlife Limited | Professional & scientific | 2019 |
| JP Plumbing and Heating (Sussex) Ltd | Construction | 2025 |
| JP Run Coaching Limited | Arts & recreation | 2023 |
| JPI Developers Ltd | Construction | 2014 |
| Jpmentors Limited | Professional & scientific | 2017 |
| JS Garden Services Limited | Administrative & support | 2023 |
| JS Trading and Investing Limited | Administrative & support | 2021 |
| JSK Consultants and Developments Ltd | Construction | 2024 |
| JSM Care Ltd | Health & social care | 2026 |
| JSZ Brickwork Ltd | Construction | 2020 |
| Jubilee Gardens (Pagham) Management Company Limited | Households | 2012 |
| Julian Munn Drainage Services Limited | Construction | 2011 |
| June Grinstead Ventures Ltd | Information & communication | 2022 |
| Juno Advisory Limited | Professional & scientific | 2021 |
| Juno Childcare Club Ltd | Health & social care | 2023 |
| Jurassic Boat Trips Limited | Transport & logistics | 2021 |
| Just Wood Flooring Ltd | Construction | 2024 |
| Justin Retail Ltd | Wholesale & retail | 2019 |
| JWP Concrete & Stone Restoration Limited | Administrative & support | 2015 |
| K & B International Transportation Services Limited | Transport & logistics | 2010 |
| K & J Retails Ltd | Wholesale & retail | 2025 |
| K Fellowes Roofing Ltd | Construction | 2018 |
| K P Designs Limited | Professional & scientific | 1992 |
| K&M Tyres Wholesale Ltd | Manufacturing | 2026 |
| K&R Services Ltd | Administrative & support | 2024 |
| K. J. Decorators Limited | Construction | 2003 |
| K.T. Fabrications Limited | Manufacturing | 1973 |
| KA1 Transport Ltd | Transport & logistics | 2022 |
| Kaba Training Solutions Limited | Education | 2022 |
| KAD Build Limited | Construction | 2024 |
| Kafor Realty Limited | Real estate | 2023 |
| Kafor Services Ltd | Health & social care | 2025 |
| Kaizen Direct Ltd | Information & communication | 2022 |