| Immaculate Proxies Ltd | Information & communication | 2025 |
| Immediate Express Limited | Transport & logistics | 2013 |
| Immo Esser Limited | Administrative & support | 2019 |
| Immobilien- UND Handelsgesellschaft Magdeburg Limited | Administrative & support | 2005 |
| Immobo Limited | Administrative & support | 2015 |
| Imolinus Limited | Administrative & support | 2012 |
| Imolinus Vaals Limited | Administrative & support | 2020 |
| IMP Gaming Limited | Wholesale & retail | 2008 |
| Impact Great Britain Limited | Wholesale & retail | 1998 |
| Impact Rugby Coaching Ltd | Arts & recreation | 2026 |
| Impact Strength and Fitness Limited | Arts & recreation | 2014 |
| Impactive IT Recruitment Ltd | Administrative & support | 2020 |
| Imperi Limited | Arts & recreation | 2019 |
| Imprestige Cars Ltd | Wholesale & retail | 2022 |
| Improve Plan Ltd | Professional & scientific | 2024 |
| Improving Lives in Yorkshire Ltd | Hospitality | 2020 |
| Improving Lives Together Ltd | Real estate | 2025 |
| IMS Care Ltd | Hospitality | 2023 |
| IMS Installations Limited | Construction | 2015 |
| IN Medics Limited | Health & social care | 2020 |
| Inbox Heroes Ltd | Extraterritorial | 2016 |
| Independent Food Co Ltd | Hospitality | 2018 |
| Independent Leisure Limited | Hospitality | 1984 |
| Index Management Limited | Other services | 2014 |
| Indian Experiences Limited | Administrative & support | 2009 |
| Indian Spice (Horbury) Ltd | Hospitality | 2020 |
| Indigo Financial Ltd | Information & communication | 2022 |
| Indulge Deserts Ltd | Hospitality | 2025 |
| Indus Takeaway Ltd | Hospitality | 2019 |
| Industrial Supply Store Ltd | Wholesale & retail | 2017 |
| Infigo Events Ltd | Administrative & support | 2020 |
| INFINI8AI Limited | Information & communication | 2022 |
| Infinity Electrical & Security Limited | Construction | 2014 |
| Infinity Group Building Services Ltd | Construction | 2020 |
| Influx (Yorkshire) Limited | Construction | 2018 |
| Infolabs Limited | Information & communication | 2022 |
| Inform Medical Limited | Health & social care | 2024 |
| Information Design Sigma Ltd | Information & communication | 2015 |
| Infosys Tech Solutions Ltd | Information & communication | 2022 |
| Infuse Industrial Services Ltd | Professional & scientific | 2008 |
| Inn Fold Farm Management Company Limited | Households | 2002 |
| Innorian Research & Development Limited | Manufacturing | 2015 |
| Innoteck Group Limited | Wholesale & retail | 2025 |
| Innovation Ethics | Wholesale & retail | 2025 |
| Innovation Quest Ltd | Information & communication | 2017 |
| Innovative Consulting Limited | Professional & scientific | 2024 |
| Innovative QA Solutions Ltd | Information & communication | 2022 |
| Innovative Skin Clinics Ltd | Health & social care | 2017 |
| Innovo Architects Ltd | Professional & scientific | 2024 |
| INQB8 CIC | Real estate | 2019 |
| INQB8 Jobs & Training CIC | Administrative & support | 2020 |
| Inselzeit Limited | Administrative & support | 2018 |
| Insha Electronics Ltd | Wholesale & retail | 2021 |
| Insite Safety Solutions Limited | Professional & scientific | 2023 |
| Inspirations Florist Ltd | Wholesale & retail | 2013 |
| Inspire Claims Limited | Extraterritorial | 2021 |
| Inspire Global Innovations Ltd | Manufacturing | 2024 |
| Inspire Mental Wellbeing Services (Imws) Ltd | Health & social care | 2025 |
| Inspire Premier Solutions Ltd | Construction | 2012 |
| Inspired Automotive Limited | Extraterritorial | 2013 |
| Inspired Building Services (NW) Ltd | Construction | 2021 |
| Inspired Buildings and Garden Rooms Ltd | Construction | 2025 |
| Inspired Childcare Ltd | Health & social care | 2024 |
| Inspiring Community CIC | Education | 2019 |
| Inspiring Generations Ltd | Health & social care | 2012 |
| Instafit Installations Limited | Construction | 2008 |
| Install Solutions - Display & Graphics Ltd | Construction | 2024 |
| Institut Fuer Kognitive Verhaltenstherapie Hessen (Ikvt) Limited | Administrative & support | 2011 |
| Instyle Hair&Beauty Ltd | Other services | 2021 |
| Insured Windows Guarantees Limited | Financial services | 1996 |
| Intafaze Entertainments Limited | Arts & recreation | 2019 |
| Intal Solutions Ltd | Administrative & support | 2024 |
| Intalekt Holdings (Wakefield) Ltd | Real estate | 2018 |
| Intalekt Property Services Limited | Real estate | 2017 |
| Intedev Ltd | Professional & scientific | 2009 |
| Integral Building Control Solutions Limited | Professional & scientific | 2012 |
| Integral Electrical Systems Ltd | Construction | 2018 |
| Integral Project Solutions Limited | Professional & scientific | 2001 |
| Integrated M&E Services Ltd | Professional & scientific | 2022 |
| Integrated Third Party Logistics Limited | Transport & logistics | 2010 |
| Integrity Northern UK Properties Limited | Real estate | 2021 |
| Intercontinental Voices Ltd | Hospitality | 2023 |
| Interior Motive (Yorks) Ltd | Other services | 2019 |
| Internal Healthcare Limited | Health & social care | 2023 |
| International Business Faderation Ltd | Administrative & support | 2025 |
| International Management & Agency Limited | Arts & recreation | 1995 |
| International Merchants SY Limited | Wholesale & retail | 2019 |
| Intrepidvan Ltd | Manufacturing | 2026 |
| Invertía Limited | Real estate | 2025 |
| Invest 1ST Limited | Real estate | 2026 |
| Investment Group Commercial Ltd | Construction | 2020 |
| Investment Group Properties Ltd | Real estate | 2022 |
| Investment Group Property Ltd | Real estate | 2023 |
| Investortas Limited | Financial services | 2015 |
| Invodec UK Limited | Construction | 2021 |
| Invotex Architectural Finishes Limited | Construction | 2020 |
| Iomms Management Ltd | Professional & scientific | 2012 |
| ION Nita Limited | Transport & logistics | 2025 |
| IP Infrastructures Limited | Information & communication | 2003 |
| IP Marygate House Limited | Real estate | 2019 |