| Ice Ice Baby Ltd | Manufacturing | 2022 |
| Iconic Installations Limited | Construction | 2014 |
| ID Gaming Limited | Other services | 2021 |
| Idea Design Consultants Ltd | Professional & scientific | 2026 |
| Ideal Gardens Creations Ltd | Administrative & support | 2026 |
| Ideal Group (UK) Ltd | Professional & scientific | 2013 |
| Ideal Signs (UK) Limited | Manufacturing | 2010 |
| Ideals (GB) Limited | Manufacturing | 2003 |
| Identix Limited | Health & social care | 2018 |
| IDK Surveying Services Ltd | Construction | 2016 |
| IFC Ltd | Manufacturing | 2024 |
| IFL TV Ltd | Information & communication | 2013 |
| Ignition Autos Essex Limited | Wholesale & retail | 2023 |
| Ignition Car Parts Limited | Wholesale & retail | 2008 |
| Ikodea Estates Limited | Real estate | 2016 |
| Ikodea UK Limited | Health & social care | 2006 |
| Ilinca Ltd | Construction | 2025 |
| ILLUMIN8 Lights Limited | Administrative & support | 2015 |
| Image Carpet and Wood Limited | Wholesale & retail | 2020 |
| Image Flooring Depot Limited | Wholesale & retail | 2008 |
| Image Window Systems Limited | Manufacturing | 1999 |
| Imatrix Ltd | Construction | 2020 |
| Imdms Ltd | Professional & scientific | 2006 |
| IMI Fire Doors Ltd | Public administration | 2025 |
| Impact Media Design Limited | Information & communication | 2010 |
| Impact Media Limited | Information & communication | 2011 |
| Impact Print Management Limited | Extraterritorial | 2010 |
| Impi Care Ltd | Administrative & support | 2019 |
| Improlife Ltd | Wholesale & retail | 2017 |
| Impropa Talent Limited | Professional & scientific | 2022 |
| Imuse Multi Concept Limited | Financial services | 2025 |
| IN Events & Promotions Limited | Other services | 2019 |
| IN Property Ltd | Construction | 2015 |
| IN the Line of Beauty Limited | Extraterritorial | 2013 |
| IN With the New Ltd | Construction | 2019 |
| Incedit Limited | Other services | 2016 |
| Incredible Brilliant Youth CIC | Education | 2016 |
| Indecon Holdings Limited | Financial services | 2023 |
| Indemnity Legal (UK) Limited | Professional & scientific | 2004 |
| Independent Installations & Refurbishments Ltd | Administrative & support | 2013 |
| Industrial Machinery Removals Ltd | Transport & logistics | 2024 |
| Industry Parent Limited | Arts & recreation | 2025 |
| Infinite Aces Ltd | Administrative & support | 2017 |
| Info Tracker Ltd | Wholesale & retail | 2022 |
| Inicio Training and Wellness Ltd | Arts & recreation | 2023 |
| Inigo Elitec Limited | Information & communication | 2024 |
| Inka Belle Ltd | Other services | 2014 |
| Innate Property Management Ltd | Real estate | 2023 |
| Innate Property Ventures Ltd | Real estate | 2023 |
| Inner Beauty Makeup Limited | Other services | 2023 |
| Inner Green Ltd | Manufacturing | 2008 |
| Innovate Property Ventures Ltd | Real estate | 2025 |
| Innovation Services Limited | Wholesale & retail | 1986 |
| Innovative Business Intelligence Ltd | Information & communication | 2011 |
| Inside Digital Limited | Information & communication | 2018 |
| Insight Essex Ltd | Education | 2024 |
| Inspire and Innovate Ltd | Professional & scientific | 2021 |
| Inspire UK Properties Ltd | Real estate | 2024 |
| Inspired Coaching Ltd | Education | 2024 |
| Inspired Journeys by Kathryn Limited | Administrative & support | 2026 |
| Inspired Publishing Limited | Information & communication | 2013 |
| Install UK Essex Limited | Construction | 2014 |
| Installation Test Licencing Ltd | Transport & logistics | 2019 |
| Instant Demolition Ltd | Construction | 2023 |
| Integrity Assured Limited | Professional & scientific | 2015 |
| Interlec Contracting Ltd | Construction | 2023 |
| International Airport Visual and Navigational Aids Limited | Wholesale & retail | 1979 |
| International Relocation Management Limited | Extraterritorial | 2014 |
| Into Plumbing and Heating Ltd | Construction | 2021 |
| Inventis Limited | Professional & scientific | 2005 |
| Invest Smart Ltd | Real estate | 2025 |
| Investco Trade Limited | Financial services | 2016 |
| Investnbet Ltd | Information & communication | 2023 |
| Invictus Control Solutions (UK) Ltd | Construction | 2026 |
| Invisible INK Spmu, Medical & Removal Ltd | Other services | 2023 |
| Irchester Lakes Limited | Agriculture & fishing | 2017 |
| Iron Triangle Limited | Information & communication | 2024 |
| Isaacs Car Company Limited | Wholesale & retail | 2018 |
| Iscuran Consult Limited | Professional & scientific | 2024 |
| IT Palmer Limited | Information & communication | 2023 |
| It's Five O'Clock Somewhere Ltd | Wholesale & retail | 2020 |
| ITC Flooring Limited | Wholesale & retail | 2022 |
| Iteamise Inventories Ltd | Households | 2023 |
| Its-Sra Limited | Information & communication | 2024 |
| ITT Comms Ltd | Information & communication | 2012 |
| IUL Company Ltd | Real estate | 2025 |
| J B Interiors Ltd | Construction | 2008 |
| J B Scott Construction Ltd | Construction | 2025 |
| J C Tiling Contractors Limited | Construction | 2017 |
| J Crook Property Limited | Real estate | 2024 |
| J D Etchells Ltd | Construction | 2017 |
| J D T Works Limited | Information & communication | 2012 |
| J F Plumbing & SON Limited | Construction | 2019 |
| J L Environmental Limited | Professional & scientific | 2004 |
| J Labour Ltd | Construction | 2019 |
| J Peacock Home Insulation Solutions Ltd | Construction | 2021 |
| J Reade Interiors Ltd | Construction | 2025 |
| J Wright Carpentry Services Ltd | Construction | 2002 |
| J& J Building Constructions Ltd | Construction | 2012 |
| J&L Key Properties Ltd | Real estate | 2021 |