| Invasion LAB Ltd | Professional & scientific | 2019 |
| Investalp Limited | Financial services | 2015 |
| Invicta Brands Limited | Administrative & support | 2024 |
| Invicta Cricket Coaching Limited | Arts & recreation | 2015 |
| Invicta Domains Limited | Information & communication | 2024 |
| Invicta Internet Limited | Information & communication | 2024 |
| Invicta Marketing Limited | Professional & scientific | 2024 |
| Invicta Pressing Works Ltd | Manufacturing | 2020 |
| Invicta Projects Ltd | Construction | 2018 |
| Invicta Tenens Limited | Financial services | 2024 |
| Invisible Technologies UK Limited | Information & communication | 2025 |
| Inviva Ltd | Information & communication | 2021 |
| Inwell Limited | Professional & scientific | 2022 |
| Iptamet Ltd | Wholesale & retail | 2014 |
| Iptf Limited | Financial services | 2019 |
| IPW Technologies Ltd | Manufacturing | 2022 |
| Iron Oxide Consulting Ltd | Information & communication | 2017 |
| Ironcrafts (Stotfold) Limited | Real estate | 1949 |
| Irpcom Creative Industries Ltd | Professional & scientific | 2016 |
| Isaac Rose Properties Ltd. | Construction | 2004 |
| Isaacs Associates Limited | Health & social care | 2005 |
| Isabella Grace Limited | Wholesale & retail | 2009 |
| Isap Academy Ltd | Education | 2021 |
| Isimo Audio Limited | Information & communication | 2015 |
| Isla Blue Consulting Limited | Professional & scientific | 2025 |
| Issuelab Limited | Information & communication | 2020 |
| IT Systems Consultancy Limited | Information & communication | 2011 |
| Italb Ltd | Hospitality | 2021 |
| Italceramic Ltd. | Wholesale & retail | 2002 |
| Itap Consultancy Limited | Arts & recreation | 2014 |
| Itaris Properties (Tunbridge Wells) Limited | Real estate | 1983 |
| Itaris Properties Limited | Real estate | 1972 |
| Itaxi Ltd | Transport & logistics | 2023 |
| Itchy Fish Productions Limited | Information & communication | 2017 |
| Itec Systems Limited | Information & communication | 1998 |
| Ithinkitsme LLP | | 2014 |
| Itza Consulting Ltd | Information & communication | 2026 |
| IV Projects Limited | Construction | 2024 |
| Ivanov Couriers Ltd | Transport & logistics | 2020 |
| Ivor Thomas (Amusements) Limited | Other services | 1976 |
| IVY Allen Developments Limited | Real estate | 2016 |
| IVY Lane Property Limited | Construction | 2021 |
| IVY Tuition Ltd | Education | 2023 |
| Ivère London Limited | Other services | 2025 |
| IWP Corporation Limited | Information & communication | 2010 |
| Iyer HR Services Ltd | Administrative & support | 2017 |
| J & D Francis Plumbing & Heating LLP | | 2022 |
| J & D Properties Limited | Construction | 1998 |
| J & M Properties Bodiam LLP | | 2005 |
| J & M Scaffolding (South East) Ltd | Construction | 2021 |
| J a Bulled Group Ltd | Construction | 2025 |
| J Algo Tech Limited | Information & communication | 2015 |
| J and M Optical Ltd | Wholesale & retail | 2023 |
| J Butler Property Assets Limited | Real estate | 2025 |
| J Butler Property Management LLP | | 2025 |
| J E Bennett Law Trust Corporation | Professional & scientific | 2019 |
| J Ferguson Consultancy (UK) Limited | Financial services | 2012 |
| J Ferguson Consultancy LLP | | 2012 |
| J Fletcher Holdings Ltd | Real estate | 2025 |
| J G W Consultants Limited | Construction | 2003 |
| J Garran Consultancy Limited | Information & communication | 2015 |
| J Greenman Builders and Glaziers Limited | Construction | 2012 |
| J H Heating Ltd | Construction | 2013 |
| J Langstaff Ltd | Construction | 2012 |
| J Miller & Co Ltd | Extraterritorial | 2009 |
| J N Smart Repair Services Limited | Wholesale & retail | 2004 |
| J Skitt & Sons Limited | Administrative & support | 1997 |
| J Sutton Holdings Ltd | Financial services | 2022 |
| J T Edwards Ltd | Construction | 2010 |
| J W a Investments Limited | Real estate | 2014 |
| J&M Window Cleaning Limited | Administrative & support | 2023 |
| J.A. Sales & Co Ltd | Wholesale & retail | 2025 |
| J.E.Mann Contractors Limited | Construction | 2016 |
| J.H.W. Hodson Limited | Financial services | 1996 |
| J.J. Huber (Investments) Limited | Real estate | 1948 |
| J.S. Coms Ltd | Wholesale & retail | 2019 |
| J.W Broadcast Ltd | Information & communication | 2024 |
| J.W. Hall & SON Limited | Real estate | 1932 |
| J1D Ltd | Agriculture & fishing | 2025 |
| J2K Retail Ltd | Wholesale & retail | 2022 |
| Jaac Holdings Ltd | Professional & scientific | 2018 |
| JAB! JAB! JAB! Ltd | Information & communication | 2023 |
| Jabba Properties Holdings Limited | Financial services | 2023 |
| Jabcfo Limited | Professional & scientific | 2024 |
| Jack Hone Design Ltd | Manufacturing | 2016 |
| Jackson and Swaffield Limited | | 1978 |
| Jackson-Moore Associates LLP | | 2007 |
| Jackson-Moore Limited | Other services | 2015 |
| Jacob G & Co Limited | Construction | 2025 |
| Jacofloor Ltd | Wholesale & retail | 2014 |
| Jade Bisram Production Ltd | Information & communication | 2019 |
| Jade Phoebe Williams Limited | Professional & scientific | 2021 |
| JAE CT Enterprises Limited | Administrative & support | 2017 |
| Jale Consultancy Limited | Professional & scientific | 2019 |
| Jamaica Blue (Tunbridge Wells) Ltd | Hospitality | 2025 |
| Jamb Investments Limited | Financial services | 2018 |
| James Crates Consultancy Limited | Information & communication | 2024 |
| James Donnelly Therapy Ltd | Health & social care | 2025 |
| James Massey Design Limited | Administrative & support | 2004 |
| James Place Horsham Ltd | Construction | 2022 |