| Horton Partners Ltd | Other services | 2016 |
| House Music Collective Limited | Professional & scientific | 2019 |
| Howitt Properties 2 Ltd | Real estate | 2024 |
| HR Presents Limited | Information & communication | 2019 |
| Huddle Collection Limited | Wholesale & retail | 2021 |
| Hudson Consulting Group Limited | Professional & scientific | 2018 |
| Humanayz Ltd | Information & communication | 2014 |
| Hunnisett’S Tree Surgeon & Garden Services Ltd | Administrative & support | 2017 |
| Hurst Construction and Electrical Ltd | Construction | 2021 |
| Huzback Securities Limited | Financial services | 1962 |
| I Dart (UK) Limited | Manufacturing | 2015 |
| I Fit Flooring Limited | Construction | 2015 |
| Idaluna Labs Ltd | Information & communication | 2026 |
| Ideas Create Solutions Ltd | Professional & scientific | 2023 |
| IDG Maritime Limited | Professional & scientific | 2000 |
| Iflor Limited | Construction | 2024 |
| Imperial Building Conservation Ltd | Wholesale & retail | 2022 |
| Imperial Building Ltd | Construction | 2002 |
| Imperial Way Management Ltd | Real estate | 2020 |
| Incam Digital Surveillance Limited | Administrative & support | 1995 |
| Indigo BEA Limited | Real estate | 2020 |
| Intelligent Realities Limited | Information & communication | 2018 |
| International Mounted Games Association | Arts & recreation | 2004 |
| Introtrade International Limited | Professional & scientific | 1987 |
| Invicta Handmade Tiles Ltd | Wholesale & retail | 2023 |
| Ipdi Limited | Construction | 1999 |
| IPT Members Limited | Other services | 2022 |
| J Novis Services Limited | Other services | 2018 |
| J&F Fruiterers Ltd | Wholesale & retail | 2018 |
| J&J Love Properties Limited | Real estate | 2022 |
| J.E.A.N Property Holdings Ltd | Real estate | 2024 |
| J.L. Andrews Building Limited | Construction | 2003 |
| J.R. Fairhall Builder & Contractor Limited | Construction | 2002 |
| J.T. Commercial Property Limited | Real estate | 2006 |
| Jamben Consulting Limited | Hospitality | 2019 |
| James Black Management Limited | Other services | 2010 |
| James Robert Construction Ltd | Construction | 2022 |
| James Rummery International Horse and Bloodstock Transport Ltd | Transport & logistics | 2025 |
| Jarvis Accountancy Ltd | Professional & scientific | 2019 |
| JC Electric Solutions Ltd | Construction | 2025 |
| JC Leisure Motorhomes Ltd | Other services | 2023 |
| JD Architects Limited | Professional & scientific | 2017 |
| Jdrd Limited | Professional & scientific | 2021 |
| JEB Technical Limited | Construction | 2013 |
| Jeco Projects Ltd | Construction | 2018 |
| Jellicoe Creative Limited | Other services | 2025 |
| Jempson Holdings Limited | Transport & logistics | 2009 |
| Jempsons Bakers Limited | Wholesale & retail | 1999 |
| Jempsons Local Limited | Wholesale & retail | 2022 |
| Jempsons Supermarkets Limited | Wholesale & retail | 2006 |
| Jespi Co Ltd | Professional & scientific | 2023 |
| Jessamine Farm Ltd | Hospitality | 2023 |
| JIM Northover Limited | Professional & scientific | 2011 |
| JJH Safety Services Limited | Professional & scientific | 2017 |
| JJM Associates Limited | Real estate | 2008 |
| JJS Partners (Richmond) Ltd | Professional & scientific | 2018 |
| Jlcx Limited | Information & communication | 2022 |
| JM Crisford Limited | Real estate | 2016 |
| JMP Housing Ltd | Real estate | 2024 |
| JNJ Real Estate Solution Ltd | Real estate | 2026 |
| John Cleary Consultancy Ltd | Professional & scientific | 2019 |
| John Langridge Motorsport Ltd | Arts & recreation | 2020 |
| John Phillips Associates Limited | Real estate | 2003 |
| Jolly Good Fellow Ltd | Real estate | 2021 |
| Joseph Wellings Limited | | 1940 |
| JRS (Sussex) Limited | Manufacturing | 2013 |
| JRS Southern Ltd | Manufacturing | 2020 |
| JTL Management Ltd | Households | 2021 |
| Julia Smith Lighting Limited | Information & communication | 2008 |
| Julie Kemp Limited | Administrative & support | 2005 |
| Justgotyou Ltd | Wholesale & retail | 2025 |
| JW Counsel Limited | Professional & scientific | 2017 |
| K12 Base Ltd | Information & communication | 2025 |
| Kdas Consulting Limited | Administrative & support | 2011 |
| Kent and Sussex Garage Conversions Ltd | Construction | 2025 |
| Kent Remediation Ltd | Water & waste | 2024 |
| Kerb Technology Ltd | Information & communication | 2026 |
| Kettenrad Limited | Professional & scientific | 2020 |
| KHR Brothers Limited | Wholesale & retail | 2025 |
| KHU Pubs Limited | Hospitality | 2024 |
| Kibblejoy Ltd | Wholesale & retail | 2024 |
| Kiko's Cat Cafe Ltd | Hospitality | 2023 |
| Killer Instinct Airsoft Ltd | Wholesale & retail | 2024 |
| Kilo Consulting Limited | Professional & scientific | 2024 |
| Kingfisher Business & Consultancy Services Limited | Professional & scientific | 2013 |
| Kiossk Management Limited | Construction | 2012 |
| Klaritas Limited | Administrative & support | 2025 |
| KLM Mechanical Services Ltd | Manufacturing | 2022 |
| Klyv Ltd | Information & communication | 2021 |
| Knoops (Pro) Ltd | Wholesale & retail | 2022 |
| Kolumbus Solutions Limited | Administrative & support | 2024 |
| KP About Tube Ltd | Construction | 2026 |
| Kpdc Limited | Financial services | 2020 |
| L & M Fire Protection Limited | Construction | 2003 |
| L.Wheeler and Sons(Maldon)Limited | Agriculture & fishing | 1952 |
| Lagdon Construction Limited | Construction | 2016 |
| Land Lake and Woodland Clearance Limited | Administrative & support | 2003 |
| Lang and Shaw Ltd | Professional & scientific | 2021 |
| Langham House Projects Ltd | Wholesale & retail | 2011 |
| Larkstone Property Management Ltd | Real estate | 2010 |