| Implant Solutions Limited | Health & social care | 2021 |
| Incito Media Limited | Administrative & support | 2008 |
| Indiy & Co Services Ltd | Construction | 2017 |
| Industrial Heating and Cooling Ltd | Construction | 2017 |
| Infinity Document Solutions Limited | Administrative & support | 2012 |
| Infoanalytics Ltd | Professional & scientific | 2025 |
| Inna Ltd | Transport & logistics | 2020 |
| Inspection Services (U.K.) Limited | Professional & scientific | 1992 |
| Inspired Travel Group Limited | Administrative & support | 1987 |
| Instant Swim School Ltd | Education | 2021 |
| Intea Ltd | Wholesale & retail | 2021 |
| Intention Osteopathy Ltd | Health & social care | 2023 |
| International Development Agency of Kazakhstan | Wholesale & retail | 2016 |
| International Student Network Ltd | Education | 2025 |
| Interplast (UK) Ltd | Administrative & support | 2000 |
| Investment Control Services UK Ltd | Information & communication | 2020 |
| Invicta Pallets Limited | Transport & logistics | 2011 |
| IP Project Management Ltd | Professional & scientific | 2026 |
| Iris Investments Limited | Financial services | 2013 |
| Irisbrad Reliable Healthcare Ltd | Health & social care | 2022 |
| Islandbay Developments Limited | Construction | 2005 |
| Itrust Developments Ltd | Information & communication | 2023 |
| Itrust Holdings Limited | Information & communication | 2026 |
| Iver Property Management Co Ltd | Real estate | 2018 |
| Ivywell Personal Development Limited | Professional & scientific | 2015 |
| J & S Uwins Limited | Professional & scientific | 2011 |
| J J M Ault Tree Surgeons Limited | Administrative & support | 2009 |
| J K Russell & SON Ltd | Construction | 2015 |
| J&D Railway Ltd | Construction | 2016 |
| J&L Contractors Ltd | Construction | 2022 |
| J&M Heating & Plumbing Ltd | Construction | 2021 |
| J. Welsh Marketing Limited | Administrative & support | 2007 |
| J.P.V. Brickwork Ltd | Construction | 2023 |
| Jack Stanley Holdings Limited | Financial services | 2018 |
| Jack Stanley Homes Limited | Administrative & support | 2015 |
| Jackson & Nunn Limited | Manufacturing | 2025 |
| Jacqueline-Annette Hales | Extraterritorial | 2024 |
| Jaddex Electrical Ltd | Extraterritorial | 2020 |
| Jaguar Contract Cleaning Services Limited | Administrative & support | 2009 |
| James Consultancy Service Limited | Administrative & support | 2014 |
| James Wright Property Lettings Ltd | Real estate | 2019 |
| Jameson Management Ltd | Administrative & support | 2013 |
| Jasmine Naylor Limited | Other services | 2019 |
| Jason Millan Limited | Hospitality | 2013 |
| Jayar Components Limited | Wholesale & retail | 1976 |
| JB Plastering and Construction Services Ltd | Manufacturing | 2026 |
| JC Bespoke Ltd | Manufacturing | 2021 |
| Jcmeters Limited | Water & waste | 2020 |
| Jctech Electrical LLP | | 2026 |
| JDC Software Solutions Ltd | Information & communication | 2025 |
| Jedi Property Services Ltd | Construction | 2022 |
| Jeffery Garden and Gifts Limited | Wholesale & retail | 2018 |
| Jensen Brothers Ltd | Financial services | 2021 |
| JFA 4FRONT Plumbing Solutions Limited | Construction | 2026 |
| Jfdi Services Limited | Arts & recreation | 2004 |
| JG Plumbing and Heating Ltd | Construction | 2023 |
| JHS Sussex Limited | Real estate | 2024 |
| JIL Property Group Limited | Real estate | 2025 |
| Jjcj Solutions Limited | Administrative & support | 2026 |
| Jjsk Properties Ltd | Real estate | 2018 |
| JLM Plant Services Limited | Wholesale & retail | 2012 |
| JLP Services (Kent) Ltd | Construction | 2020 |
| JLR Property Holdings Limited | Households | 2024 |
| JMC 22 Limited | Financial services | 2023 |
| JN Haulage Kent Limited | Transport & logistics | 2017 |
| JNF Properties Ltd | Real estate | 2025 |
| JOE Clarke Installation Limited | Construction | 2016 |
| JOE Thomas Digital Imaging Limited | Professional & scientific | 2011 |
| John Appleton Ltd | Administrative & support | 2007 |
| John Sharpe Stunts Limited | Arts & recreation | 2021 |
| John Street Homes Limited | Real estate | 2022 |
| John White Vehicle Repairs Ltd | Wholesale & retail | 2008 |
| Johnny T Frames Ltd | Manufacturing | 2021 |
| Johnson 3 Limited | Real estate | 2024 |
| Joma Property Ltd | Real estate | 2019 |
| Joyce Magonde Limited | Health & social care | 2015 |
| JP Martin Construction Ltd | Construction | 2019 |
| JP Rafferty Homes Limited | Construction | 2021 |
| JP84 Ltd | Professional & scientific | 2023 |
| JR Building Services Kent Ltd | Construction | 2024 |
| Jrgs Construction Limited | Construction | 2020 |
| JRS Skipper and Marine Services Ltd | Manufacturing | 2026 |
| Jsds Tech Ltd | Manufacturing | 2024 |
| JSI Plumbing Ltd | Construction | 2019 |
| Jtta Ltd | Information & communication | 2018 |
| Juniper Consulting Services Ltd | Administrative & support | 2015 |
| Jutro Health Ltd | Health & social care | 2025 |
| Jutro Ltd | Financial services | 2025 |
| JWB Property Investment Ltd | Real estate | 2023 |
| Jwband Limited | Arts & recreation | 2025 |
| K Charles Haulage Ltd | Transport & logistics | 2017 |
| K D Rigging and Training Limited | Construction | 2011 |
| K.M.H. Communications Limited | Information & communication | 1984 |
| KAB Healthcare Limited | Wholesale & retail | 2021 |
| Kaizen Impact Investment Ltd | Professional & scientific | 2023 |
| Kalm Developments Kent Ltd | Real estate | 2025 |
| Kalo Limited | Wholesale & retail | 2020 |
| Kamenov Ltd | Transport & logistics | 2017 |
| Katevend Limited | Administrative & support | 1999 |
| KB Services Plant Limited | Construction | 2025 |