| Ignite Heating and Cooling Ltd | Construction | 2011 |
| IK Philip Ltd | Wholesale & retail | 2022 |
| Ikebana Ltd | Wholesale & retail | 2020 |
| Ikon Marketing Ltd | Professional & scientific | 2024 |
| Ilex Alba Ltd | Wholesale & retail | 2022 |
| Ilmp Ltd | Wholesale & retail | 2025 |
| ILW Engineering Ltd | Professional & scientific | 2024 |
| Imaginary Conversations CIC | Arts & recreation | 2023 |
| Immax Limited | Real estate | 2023 |
| Immerse Safety Ltd | Professional & scientific | 2024 |
| Impact Internet Limited | Information & communication | 2022 |
| Imperial Hotel (GT. Yarmouth) EOT Trustee Company Limited | Hospitality | 2023 |
| Imperial Hotel(Gt.Yarmouth)Limited | Hospitality | 1961 |
| Imperial Lodge GY Ltd | Hospitality | 2026 |
| Imperial Offshore Limited | Professional & scientific | 2006 |
| Imperium Electrical Contractors Ltd | Construction | 2018 |
| Imphire E-Scooter Rentals Ltd | Administrative & support | 2024 |
| Imports Plus Ltd | Wholesale & retail | 2015 |
| IN Business (UK) Limited | Professional & scientific | 2011 |
| In-Sink Property Care Ltd | Other services | 2019 |
| INA Healthcare Limited | Health & social care | 2012 |
| Incense World Limited | Wholesale & retail | 2024 |
| Inclusiva Ltd | Professional & scientific | 2024 |
| Independent Lifting Services Limited | Manufacturing | 2001 |
| Indian Food Club Limited | Hospitality | 2021 |
| Infinite Sidequests Limited | Information & communication | 2018 |
| Infinity Eighth Ltd | Financial services | 2024 |
| Infinity Network Services Limited | Construction | 2025 |
| Infobond Limited | Administrative & support | 1993 |
| Information & Content Services 2025 Limited | Information & communication | 2020 |
| Ingenii Resource Limited | Administrative & support | 2016 |
| INK Asylum Creative Limited | Arts & recreation | 2024 |
| Innovation Hill Ltd | Information & communication | 2019 |
| Inspec 180 Ltd | Professional & scientific | 2021 |
| Inspire Conservatories Limited | Construction | 2017 |
| Interface Engineering Services Limited | Mining & quarrying | 2001 |
| Interful Limited | Wholesale & retail | 2021 |
| International Safety Group Limited | Administrative & support | 2020 |
| Intervention Solutions Limited | Mining & quarrying | 2026 |
| Intwood Power Limited | Real estate | 2023 |
| Ipswich Road Surgery Limited | Health & social care | 2012 |
| Iron Warehouse Ltd | Other services | 2021 |
| Isaclearspace Solutions Limited | Water & waste | 2026 |
| Iskis Transport Ltd | Transport & logistics | 2020 |
| Isledon Holdings Limited | Health & social care | 2020 |
| Istanbul Delight Pizza and Kebab House Ltd | Hospitality | 2019 |
| IT at C Ltd | Information & communication | 2006 |
| It-C Support Solutions Ltd | Information & communication | 2009 |
| Itracked Limited | Information & communication | 2015 |
| Itron (U.K.) Limited | Manufacturing | 1997 |
| Ived Ltd | Wholesale & retail | 2020 |
| IVY Castle Limited | Construction | 2009 |
| Ivydene Residential Home Ltd | Health & social care | 2022 |
| J & C Housing Limited | Real estate | 2019 |
| J & J Solutions Group Ltd | Professional & scientific | 2024 |
| J & S Cottages Developments Limited | Extraterritorial | 2015 |
| J & S Cottages Limited | Hospitality | 2015 |
| J + S Property (UK) Limited | Construction | 2005 |
| J Abel Property Holdings Ltd | Real estate | 2025 |
| J and R Creations Limited | Arts & recreation | 2024 |
| J C a Cleaning Limited | Administrative & support | 2006 |
| J D Taverns Limited | Hospitality | 2004 |
| J D Taverns PUB Company (Hopton) Limited | Hospitality | 2016 |
| J Dixon & SON Contractor Limited | Construction | 2011 |
| J Dunthorne Oilfield Services Ltd | Professional & scientific | 2025 |
| J L Wholesale Ltd | Wholesale & retail | 2018 |
| J Law Property Limited | Real estate | 2017 |
| J M Peace Consultancy Ltd | Professional & scientific | 2021 |
| J M R Property (Norfolk) Limited | Financial services | 2025 |
| J Millington Home Improvements Limited | Administrative & support | 2011 |
| J P C O'Donnell Limited | Health & social care | 2010 |
| J P Southern Limited | Wholesale & retail | 2011 |
| J P W (Norfolk) Limited | Construction | 2009 |
| J R Pitchers Limited | Wholesale & retail | 1996 |
| J R Stevenson UK Ltd | Construction | 2016 |
| J Roberts Field Services Limited | Professional & scientific | 2018 |
| J S Kalsi Ltd | Health & social care | 2013 |
| J V Orthodontics Limited | Health & social care | 2017 |
| J Wood Painting & Decorating Ltd | Construction | 2019 |
| J Z Marine Services Limited | Manufacturing | 2018 |
| J&A Building Contractors Ltd | Construction | 2019 |
| J&C Properties (Norfolk) Limited | Construction | 2019 |
| J&S Facilities Group Ltd | Construction | 2025 |
| J-All Environmental Ltd | Water & waste | 2023 |
| J.A.K Plumbing and Heating Ltd | Construction | 2025 |
| J.D.K. Developments Limited | Construction | 2001 |
| J.E.L Properties Ltd | Real estate | 2022 |
| J.F. Birch Limited | Professional & scientific | 2024 |
| J.S.M. Home Improvements Ltd | Construction | 2004 |
| J.W.Munnings Limited | Construction | 1955 |
| J.W.Munnings Properties Limited | Real estate | 1965 |
| J3 Systems Ltd | Professional & scientific | 2016 |
| Jackman Trading Limited | Wholesale & retail | 2023 |
| JAD Training & Education Consultants Limited | Education | 2021 |
| JAE Clean Ltd | Administrative & support | 2021 |
| JAJ Engineering Ltd | Professional & scientific | 2025 |
| JAJ Security Limited | Administrative & support | 2025 |
| Jake Ace Magician Ltd | Arts & recreation | 2021 |
| James Adam Property Ltd | Real estate | 2018 |
| James Charles Mortgage and Protection Limited | Financial services | 2018 |