| Implementation Construction Innovative System Ltd | Construction | 2024 |
| In-House Creative Ltd | Other services | 2020 |
| Inc Multiservices Ltd | Information & communication | 2023 |
| Inc Stable BIZ Ltd | Professional & scientific | 2023 |
| Inchwater Ltd | Health & social care | 2011 |
| Incroyable Corp Ltd | Wholesale & retail | 2021 |
| Independent Vessel Holdings Ltd | Financial services | 2020 |
| Independent Vessel Operations Services Limited | Transport & logistics | 2007 |
| Independent Vessels Ltd | Transport & logistics | 2020 |
| Industrial Infrastructure Limited | Professional & scientific | 2006 |
| Infi-Nity Soins Invest Ltd | Health & social care | 2021 |
| Infi-Nity Soins Ltd | Health & social care | 2021 |
| Info Commerce Limited | Administrative & support | 1994 |
| Info Secretary Limited | Extraterritorial | 1994 |
| ING Construction Management Services Limited | Professional & scientific | 2023 |
| Inspire Minds Ignite Education Limited | Education | 2025 |
| INT Capital House PLC | Extraterritorial | 2023 |
| INT Salient Inc PLC | Extraterritorial | 2023 |
| Int.Business Booster Ltd | Professional & scientific | 2021 |
| International Business Invest Ltd | Extraterritorial | 2022 |
| International Companie of Covering Ltd | Extraterritorial | 2011 |
| Intumescent Systems Limited | Manufacturing | 1987 |
| Invest Management Inc. PLC | Extraterritorial | 2020 |
| Invicta Archaeological Services Ltd | Professional & scientific | 2019 |
| Invicta City Limited | Real estate | 2019 |
| Invigor Consulting Ltd | Professional & scientific | 2021 |
| Invisible Hand Software Engineering Ltd | Wholesale & retail | 2022 |
| IPH Birmingham Limited | Professional & scientific | 2018 |
| IPS Estates Kent Limited | Real estate | 2022 |
| Iristylers Ltd | Other services | 2019 |
| Irosem Property Limited | Real estate | 2018 |
| ISE Group Limited | Information & communication | 2015 |
| Isle Heritage CIC | Professional & scientific | 2021 |
| Istanbul Flames House Ltd | Hospitality | 2026 |
| IT BE Connection Ltd | Extraterritorial | 2024 |
| IT Security Ltd | Information & communication | 2020 |
| IVY Rose Bridal Boutique Limited | Wholesale & retail | 2018 |
| Ivybank Health Care Limited | Health & social care | 2010 |
| Ivybank Healthcare Trading Ltd | Health & social care | 2023 |
| IWS (Independent Window Systems) Limited | Construction | 2014 |
| Izai Ltd | Other services | 2025 |
| J & B Developments (SE) Ltd | Construction | 2021 |
| J & R Carpets Limited | Wholesale & retail | 2002 |
| J Cameron Ltd | Construction | 2015 |
| J D Sawkins Ltd | Construction | 2025 |
| J F Morrison Engineering Ltd | Manufacturing | 2019 |
| J Night Lettings Ltd | Real estate | 2021 |
| J P Services Kent Ltd | Construction | 2019 |
| J R Civil Construction Limited | Extraterritorial | 2009 |
| J&C Clearance Services Limited | Administrative & support | 2023 |
| J&F Produtions Ltd | Wholesale & retail | 2025 |
| J&T Customs Consulting Limited | Transport & logistics | 2021 |
| J.A.D.T. Property Ltd | Real estate | 2025 |
| Jade Accountancy Services Limited | Professional & scientific | 1996 |
| Jaggar & Co Accountants Limited | Professional & scientific | 2013 |
| Jaggar & Co Ltd | Professional & scientific | 2008 |
| Jaggar Street Limited | Professional & scientific | 2023 |
| Jaggar Street Travel Agents Ltd | Administrative & support | 2024 |
| Japmonkey Ltd | Wholesale & retail | 2015 |
| Jasminwebsolution Ltd | Information & communication | 2016 |
| JAY Malvern Ltd | Professional & scientific | 2023 |
| Jberry Property Ltd | Real estate | 2025 |
| Jblj DAN Ltd | Wholesale & retail | 2024 |
| JC & KC Engineering Ltd | Construction | 2019 |
| JC Bespoke Coaching Limited | Other services | 2023 |
| JC GAS Ltd | Construction | 2021 |
| Jcob Property Ltd | Construction | 2025 |
| JD Leisure Limited | Arts & recreation | 2022 |
| JED Marine Ltd | Arts & recreation | 2025 |
| Jensar Holdings Ltd | Households | 2018 |
| Jerk N Tingz LLP | | 2018 |
| JF MOT Centre (Dover) LLP | | 2021 |
| JF Motors (Dover) Ltd | Wholesale & retail | 2015 |
| JG Electrical Contractors (Kent) Ltd | Construction | 2021 |
| JGB Construct Invest Ltd | Extraterritorial | 2024 |
| JGB Estates Limited | Real estate | 2025 |
| JGB Holdings Group Limited | Financial services | 2025 |
| JHL Accountants Limited | Professional & scientific | 2003 |
| Jihnar Limited | Wholesale & retail | 2017 |
| Jimmy Dutch Limited | Real estate | 2019 |
| JJW Property Ltd | Real estate | 2021 |
| JKC Electrical Limited | Construction | 2015 |
| JKH Estates Ltd | Real estate | 2020 |
| Jkmpmp Ltd | Information & communication | 2025 |
| JL Site Management Limited | Professional & scientific | 2014 |
| JLR Beauty Ltd | Other services | 2020 |
| JM Associates Limited | Professional & scientific | 2000 |
| JM Infi Invest Ltd | Extraterritorial | 2017 |
| JM Infi Ltd | Extraterritorial | 2017 |
| Jobs-At-Sea.Com Limited | Administrative & support | 2000 |
| JOE Hentschel Limited | Transport & logistics | 2016 |
| JOE Liquid Industries Europe & UK Ltd | Extraterritorial | 2021 |
| JOE Liquid Invest Ltd | Wholesale & retail | 2021 |
| John Bullock Associates Limited | Professional & scientific | 2003 |
| John Bywater Transport Limited | Transport & logistics | 1993 |
| John MAY Limited | Professional & scientific | 2020 |
| Jonco IT & Security Ltd | Information & communication | 2025 |
| JPS Football Centre Ltd | Education | 2021 |
| JQL Belgium Ltd | Wholesale & retail | 2015 |
| JR Therapy Invest Ltd | Professional & scientific | 2024 |