| Igras Property Investments Ltd | Real estate | 2025 |
| IIIIS4NDM4NIIII Ltd | Construction | 2014 |
| IJ Services Limited | Transport & logistics | 2018 |
| Ijtg Limited | Professional & scientific | 2019 |
| IK Decor Limited | Construction | 2020 |
| IL Piccolo Francesco Ltd | Hospitality | 2020 |
| Ilienko World of Gymnastics Limited | Other services | 2012 |
| Ilumed Properties Ltd | Real estate | 1999 |
| Imedhas Nivaas Services Ltd | Real estate | 2022 |
| IMJ Direct Ltd | Wholesale & retail | 2019 |
| IMJ Transport Ltd | Transport & logistics | 2014 |
| Imodel Limited | Information & communication | 2007 |
| Imperial Electrical Solutions Ltd | Construction | 2021 |
| Imperial Medical Care Ltd | Health & social care | 2010 |
| Imperial Tuition Ltd | Education | 2024 |
| Imprint Marketing Ltd | Manufacturing | 2007 |
| Impulsio Ltd | Wholesale & retail | 2023 |
| IN2CARE Ltd | Health & social care | 2020 |
| IN2CLEAN 2021 Ltd | Administrative & support | 2021 |
| IN2GROUP 2020 Ltd | Financial services | 2020 |
| IN2HOMES 2021 Ltd | Extraterritorial | 2022 |
| IN2SPORT 2020 Ltd | Health & social care | 2020 |
| Inbc Limited | Information & communication | 2001 |
| Incredible Experiences Limited | Administrative & support | 2010 |
| Indeeit Ltd | Information & communication | 2022 |
| Independent Consulting Associates Ltd | Professional & scientific | 2022 |
| Independent Healthcare Associates Limited | Other services | 2024 |
| Independent Training Standards Scheme and Register Limited | Professional & scientific | 2000 |
| Indie Shorts Productions Ltd | Information & communication | 2020 |
| Indigenius Inc Ltd | Transport & logistics | 2012 |
| Indira Business Solutions Limited | Information & communication | 2015 |
| Indispensable Care Ltd | Administrative & support | 2018 |
| Indo-British Cultural Foundation | Health & social care | 2018 |
| Infinity Business Solutions Limited | Information & communication | 2004 |
| Infocompass IT Limited | Wholesale & retail | 2015 |
| Infos Solutions Limited | Information & communication | 1996 |
| Infrared Systems Group Ltd | Manufacturing | 2011 |
| ING Finance Solution Limited | Information & communication | 2010 |
| ING Home Solutions Ltd | Administrative & support | 2012 |
| Ingenuitysolutions Limited | Extraterritorial | 2010 |
| Ingwe Accounting Services Limited | Professional & scientific | 2017 |
| Inhabitat Design Studios Limited | Professional & scientific | 2011 |
| Initial Steps Ltd | Education | 2014 |
| Inittowinit (Berkshire) Ltd | Arts & recreation | 2026 |
| INK Emporium Ltd. | Arts & recreation | 2015 |
| Inle Homes Limited | Real estate | 2021 |
| Inle Ltd | Information & communication | 2012 |
| Innovation Agritech Group Limited | Agriculture & fishing | 2017 |
| Innovation Technology Corporation Limited | Information & communication | 2016 |
| Innovative Minds Technologies Ltd | Information & communication | 2026 |
| Insfit Ltd | Construction | 2026 |
| Insight Brand Partnerships Ltd | Professional & scientific | 2025 |
| Insight Finance Consultancy Ltd | Professional & scientific | 2020 |
| Inspiration Care Limited | Health & social care | 2007 |
| Inspired by Movement Limited | Education | 2026 |
| Inspiring Change for Children Limited | Health & social care | 2022 |
| Installux Construct Ltd | Construction | 2025 |
| Instavenues Limited | Real estate | 2015 |
| Insync Homes Group Limited | Construction | 2023 |
| Integra Subsurface Consulting Ltd | Professional & scientific | 2025 |
| Intelidata Limited | Information & communication | 2023 |
| Intelligent Enterprise Solutions Ltd | Information & communication | 2003 |
| Intelligent Security and Electrical Systems Ltd | Construction | 2017 |
| Intelligent Utilities Ltd | Extraterritorial | 2010 |
| Intelys Technology Limited | Information & communication | 2011 |
| Interact Data Limited | Arts & recreation | 1993 |
| Interactive Platforms Limited | Information & communication | 2011 |
| International Animal Relocation Services Limited | Administrative & support | 2017 |
| International Fire Installations Ltd | Public administration | 2025 |
| Inti Air Solution Ltd | Manufacturing | 2024 |
| Intl Network Logistics Ltd. | Transport & logistics | 2020 |
| Intuition Advisors Limited | Professional & scientific | 2022 |
| Inversion Robotics Ltd | Information & communication | 2024 |
| Invicta Electrical Group Ltd | Construction | 2025 |
| Invicta Talent Limited | Professional & scientific | 2026 |
| Involve Community Services | Other services | 1997 |
| Invyta Limited | Wholesale & retail | 2016 |
| Iron Birds Ltd | Arts & recreation | 2025 |
| ISL Electrical Services Limited | Construction | 2020 |
| Isle of Wight Pottery & Sensory Hub Ltd | Wholesale & retail | 2025 |
| Ispata Ltd | Manufacturing | 2020 |
| Istanbul Hair Studio Limited | Other services | 2021 |
| IT Figures Solutions Limited | Information & communication | 2015 |
| It-Conservuk Limited | Information & communication | 2008 |
| Italian Imports Limited | Wholesale & retail | 2000 |
| Iterate Limited | Professional & scientific | 2001 |
| Itesminds Technologies Limited | Information & communication | 2017 |
| Ithaca Flat Roofing Limited | Extraterritorial | 2021 |
| Ithaca Group Limited | Extraterritorial | 2015 |
| Ithaca Roofing Ltd | Construction | 2006 |
| Ithaca Roofing Services Ltd | Extraterritorial | 2021 |
| Ithaca Roofing Supplies Limited | Extraterritorial | 2015 |
| ITJ Designs Ltd | Professional & scientific | 2021 |
| Itreasure.& Co Ltd | Wholesale & retail | 2021 |
| ITS Made in Africa Ltd | Wholesale & retail | 2021 |
| Itssar Limited | Extraterritorial | 2015 |
| IU Build Limited | Construction | 2018 |
| IVI Design Limited | Manufacturing | 2020 |
| Iview Estate Ltd | Real estate | 2025 |
| Ivyglen Limited | Administrative & support | 1997 |