| Horsepower UK Ltd | Wholesale & retail | 2004 |
| HOW PHI Limited | Professional & scientific | 2016 |
| Hpes Technical Solutions Ltd | Construction | 2024 |
| HTS Land Developments Limited | Construction | 2025 |
| Huckleberry Woods Ltd. | Arts & recreation | 2017 |
| Huggins Wealth Management Limited | Financial services | 2018 |
| Human Factor Software Ltd | Information & communication | 2020 |
| Hungry Gents Limited | Hospitality | 2024 |
| Hydraulic Crane Services Limited | Construction | 1995 |
| Hydroforce Solutions Limited | Construction | 2006 |
| I DO Marketing Ltd | Extraterritorial | 2024 |
| I E J Contracts Limited | Other services | 2012 |
| I R H Lumsden Ltd | Information & communication | 2018 |
| IAM Industries Limited | Construction | 2016 |
| IAN Rule Solutions Ltd | Professional & scientific | 2016 |
| Iatefl Trading Limited | Other services | 2009 |
| ICO Stationery Limited | Professional & scientific | 2004 |
| ID Smith Construction Services Limited | Construction | 2018 |
| Ideafruit UK Limited | Agriculture & fishing | 2016 |
| Ideal Salon Ltd | Real estate | 2023 |
| Ikibiko Ltd | Professional & scientific | 2022 |
| Iliffe & Iliffe Limited | Real estate | 2020 |
| Iliffe Holdings Ltd | Real estate | 2026 |
| Illiondale Limited | Financial services | 2026 |
| Illustration Educators C.I.C. | Other services | 2022 |
| Imba Housing Ltd | Extraterritorial | 2001 |
| Individual Wellbeing Provider LLP | | 2024 |
| Ineffable Music Limited | Information & communication | 2016 |
| Ingrain Architecture Limited | Professional & scientific | 2020 |
| Innovative Beauty Limited | Information & communication | 2024 |
| Innovative Engineering Consultants Limited | Professional & scientific | 2024 |
| INSIGHT4ACTION Consultancy Limited | Professional & scientific | 2010 |
| International Association of Teachers of English AS a Foreign Language | Other services | 1990 |
| International Treasury Services (Europe) Limited | Education | 2010 |
| Interstellar Capital Limited | Professional & scientific | 2017 |
| Inversocial Ltd | Professional & scientific | 2023 |
| Invicta Building & Electrical Services Ltd | Construction | 2007 |
| Invicta Clean Energy Limited | Construction | 2006 |
| Invicta Estate Agents Limited | Real estate | 2008 |
| Invicta Homes Limited | Real estate | 2010 |
| Invicta Mortgages Limited | Real estate | 2002 |
| Invicta Property Management Limited | Real estate | 2009 |
| Invoice Monitoring Services Ltd | Administrative & support | 2022 |
| IPA Solutions Ltd | Administrative & support | 2019 |
| Irving Property Investment Ltd | Real estate | 2017 |
| IT Continuity Services Limited | Information & communication | 2021 |
| It's IP Ltd | Information & communication | 2014 |
| Itechchris Ltd | Information & communication | 2021 |
| J B Carpentry and Joinery Limited | Construction | 2004 |
| J C Birtles Ltd | Manufacturing | 2017 |
| J Clarke Developments Ltd | Construction | 2017 |
| J D & E S Barrett LLP | | 2004 |
| J D Scenic Services Ltd | Manufacturing | 2022 |
| J E House (Property) Limited | Construction | 1973 |
| J H Curling & Company Limited | Real estate | 2023 |
| J Swift Roofing Solutions Ltd | Construction | 2025 |
| J TOM Transport Ltd | Transport & logistics | 2016 |
| J W Booth & Co Limited | Real estate | 2021 |
| J&J Search Ltd | Administrative & support | 2022 |
| J.J.W.Eckley & Sons Limited | Agriculture & fishing | 1961 |
| J.K.W.Alexander Limited | Agriculture & fishing | 1951 |
| Jabpd Limited | Construction | 2018 |
| Jacks Court Farms Ltd | Real estate | 2015 |
| Jackwood Consulting Limited | Professional & scientific | 2015 |
| Jactron Ltd. | Professional & scientific | 1988 |
| JAG Outdoor Fitness Limited | Arts & recreation | 2019 |
| Jamech Building Services Limited | Construction | 2025 |
| James and Giles Limited | Construction | 2006 |
| James Savy Interiors Limited | Professional & scientific | 2007 |
| Janda Education Services Limited | Education | 2018 |
| Janine Pommer Physiotherapy Limited | Administrative & support | 2019 |
| Jas-Licking Seafood Boil Ltd | Hospitality | 2022 |
| Jasco Property Ltd | Real estate | 2025 |
| Jason Colyer Coaching Services Ltd | Health & social care | 2019 |
| Jason Decaires Taylor Limited | Arts & recreation | 2017 |
| Javanti Ltd | Real estate | 2017 |
| JAY Designs Limited | Manufacturing | 2019 |
| JAY Stores Faversham Limited | Wholesale & retail | 2023 |
| JC Builders (Kent) Ltd | Construction | 2014 |
| JCK Plastering Limited | Construction | 2026 |
| JDM Surveyors Limited | Construction | 2023 |
| Jessicuts Ltd | Other services | 2021 |
| JFB Essentials Limited | Information & communication | 2022 |
| JG Professional and Student Lets Ltd | Construction | 2007 |
| JG Residential Management Ltd | Households | 2019 |
| Jgsl LLP | | 2016 |
| Jimmy West Associates Limited | Financial services | 1995 |
| JKT 2026 Limited | Financial services | 2026 |
| JL Hydraulics Limited | Manufacturing | 2008 |
| Jmbs (South) Limited | Real estate | 2009 |
| JMP Electrical Service (Kent) Ltd | Construction | 2021 |
| John a Bensted & Partners LLP | | 2021 |
| John Graham Crabtree Ltd | Financial services | 2010 |
| John Jarvis Holdings Limited | Professional & scientific | 1911 |
| John Nason Limited | Construction | 2013 |
| Join Studio Ltd | Manufacturing | 2024 |
| Joined UP Thinking JUT C.I.C. | Administrative & support | 2016 |
| JON Gauld Residential Lets Ltd | Real estate | 2017 |
| Jotmon Ltd | Transport & logistics | 2020 |
| JP KAG Ltd | Health & social care | 2012 |