| Icomb Developments Ltd | Construction | 2010 |
| Icon Flats Ltd | Real estate | 2021 |
| Icon Holiday Homes Ltd | Real estate | 2024 |
| Icon Homes Ltd | Real estate | 2026 |
| Icon Homes Private Ltd | Real estate | 2020 |
| Icon Properties Newcastle Ltd | Construction | 2020 |
| Icor Systems Ltd | Professional & scientific | 2016 |
| ICR Fibre Optics Limited | Information & communication | 2014 |
| ICR Publications Ltd | Information & communication | 2017 |
| ID Cydonia Ltd | Financial services | 2021 |
| ID Property Plus Ltd | Households | 2026 |
| Idap-Ara CIC | Education | 2024 |
| Idas Global Holdings Limited | Financial services | 2021 |
| Idea Asset Limited | Real estate | 2022 |
| Idea Energy Surveys Limited | Professional & scientific | 2007 |
| Idea Junkies Ltd | Information & communication | 2022 |
| Ideal Dental Limited | Health & social care | 2021 |
| Ideal Properties (NE) Limited | Real estate | 2015 |
| Ideal Solutions NE Ltd | Administrative & support | 2025 |
| Ideal Transact Ltd | Professional & scientific | 2025 |
| Ideas for Change Consulting Limited | Professional & scientific | 2015 |
| Ideas Limited | Professional & scientific | 2002 |
| Idilico Ltd | Real estate | 2022 |
| Idle Mill Limited | Hospitality | 2019 |
| Idos Health and Wellbeing CIC | Health & social care | 2021 |
| Idrees Group Ltd | Professional & scientific | 2019 |
| Idyn Pizza Ltd | Hospitality | 2024 |
| IE Signs Limited | Manufacturing | 2007 |
| IEF Investments Limited | Real estate | 2024 |
| Ienergi Ltd | Professional & scientific | 2025 |
| Ifective Beauty Limited | Wholesale & retail | 2025 |
| IFIX4LESS 1 Limited | Other services | 2019 |
| Ifixpc&Mobiles Limited | Other services | 2016 |
| IFS Proficiency Consulting Ltd | Information & communication | 2020 |
| IFS Property Limited | Real estate | 2018 |
| Igaware Limited | Information & communication | 2001 |
| IGF Consultancy Services Ltd | Professional & scientific | 2018 |
| Igloo Imaging Limited | Administrative & support | 2017 |
| Igsn UK Ltd | Wholesale & retail | 2018 |
| IHC FHP Limited | Manufacturing | 1986 |
| IHC Merwede UK Limited | Professional & scientific | 2007 |
| Ihdy Limited | Information & communication | 2023 |
| Ihelena Ltd | Education | 2024 |
| Ihhp Property Ltd | Real estate | 2025 |
| III Management Ltd | Real estate | 2026 |
| IIP Limited | Real estate | 2024 |
| Ijesports Limited | Information & communication | 2021 |
| IJI Limited | Health & social care | 2007 |
| IJM Wind Ltd | Energy | 2021 |
| Ikid Ltd | Wholesale & retail | 2025 |
| Ikigai UK Media Ltd | Wholesale & retail | 2025 |
| Ikonic Bathrooms & Tiles Ltd | Wholesale & retail | 2017 |
| Ikonic Properties Limited | Real estate | 2016 |
| Iksuda Therapeutics Limited | Professional & scientific | 2007 |
| Ikwa Consulting Limited | Professional & scientific | 2023 |
| Ikwa Ltd | Information & communication | 2017 |
| Ilan International Ltd | Hospitality | 2023 |
| Ilara Consulting Limited | Professional & scientific | 2012 |
| Iles Consulting Limited | Professional & scientific | 2010 |
| Iles Group Ltd | Administrative & support | 2022 |
| Ilex Construction Services Limited | Professional & scientific | 2022 |
| Ilhamz Properties Ltd | Real estate | 2022 |
| Ilharia Holdings 2 Limited | Financial services | 2024 |
| Ilharia Holdings Limited | Financial services | 2018 |
| Ilkapop Ltd | Arts & recreation | 2023 |
| Illuscriber Limited | Information & communication | 2024 |
| Illusion Hair Design Limited | Other services | 2014 |
| Illustrious Creative Ltd | Professional & scientific | 2020 |
| ILS Consultants Limited | Professional & scientific | 2021 |
| IM BPO Ltd | Information & communication | 2024 |
| Imada Lettings Limited | Real estate | 2024 |
| Image Star Signs Ltd | Professional & scientific | 2021 |
| IMAGIN8 Social Media Limited | Professional & scientific | 2025 |
| Imagine Build and Maintenance Ltd | Construction | 2016 |
| Imagine Leisure Limited | Hospitality | 2022 |
| Imani Medical Limited | Health & social care | 2023 |
| Imar Projects Ltd | Professional & scientific | 2025 |
| Imbu NE Ltd | Hospitality | 2025 |
| Imec Services Limited | Construction | 2015 |
| Imech Group Ltd | Information & communication | 2026 |
| Imersys Ltd | Information & communication | 2018 |
| Imitza Limited | Information & communication | 2004 |
| IMM Capital Limited | Financial services | 2025 |
| Immanent Associates Limited | Professional & scientific | 2012 |
| Immer Care Ltd | Health & social care | 2014 |
| Immersave Limited | Information & communication | 2024 |
| Immersional Ltd | Information & communication | 2025 |
| Immi Ltd | Manufacturing | 1999 |
| Immortal Energy International Ltd | Energy | 2021 |
| Impact Childcare and Education Ltd | Health & social care | 2013 |
| Impact Icon AI Limited | Information & communication | 2025 |
| Impact Joinery Solutions Ltd | Construction | 2026 |
| Impact Psychological Services Ltd | Education | 2020 |
| Imperia (NE) Ltd | Hospitality | 2021 |
| Imperia Ascendancy Limited | Hospitality | 2021 |
| Imperial Estates North East Limited | Real estate | 2018 |
| Imperial Technologies Ltd. | Information & communication | 2014 |
| Impress Events Ltd | Administrative & support | 2018 |
| IMS Newcastle Limited | Construction | 2024 |
| Imtiaz Fitness Ltd | Arts & recreation | 2026 |