| Hintlesham Fisheries Limited | Agriculture & fishing | 2003 |
| Historic Lotus Register Ltd | Arts & recreation | 2015 |
| HJD Power Electrical Engineers Ltd | Construction | 2024 |
| HOG Homes Ltd | Real estate | 2025 |
| HOG Roast (Essex) Ltd | Hospitality | 2019 |
| Hogarth + Farrow Limited | Manufacturing | 2025 |
| Hold Fast AI Ltd | Professional & scientific | 2025 |
| Holden Estate Agents Limited | Real estate | 2009 |
| Holmwood Securities Limited | Real estate | 1959 |
| Holt Marine Limited | Professional & scientific | 2010 |
| Home Local Southend Ltd | Real estate | 2019 |
| Home Options Ltd | Real estate | 2024 |
| Home Style Essex Ltd | Administrative & support | 2020 |
| Home-Start Essex Limited | Health & social care | 2016 |
| Homgar Limited | Wholesale & retail | 2007 |
| Honest Supplies Limited | Manufacturing | 2021 |
| Hopkins Services Ltd | Information & communication | 2024 |
| Hopping Jacks Management Company Limited | Households | 2014 |
| Horizons View Developments Limited | Construction | 2020 |
| Horsey Helper Ltd | Wholesale & retail | 2022 |
| Hoskin Financial Planning Ltd | Financial services | 2013 |
| Hosking Property Ltd | Real estate | 2019 |
| Hot Chix. Ltd | Hospitality | 2025 |
| Houghtons Building Contractors Ltd | Construction | 2019 |
| House of Hydration Ltd | Other services | 2025 |
| House of Seda Limited | Other services | 2025 |
| Houston Drylining Ltd | Administrative & support | 2017 |
| Howarth Floors Ltd | Construction | 2020 |
| Howies & Sons LLP | | 2006 |
| Howt Consultancy Limited | Information & communication | 2025 |
| HPC (Glynneath) Limited | Construction | 2013 |
| HPK Consulting (UK) Ltd | Professional & scientific | 2024 |
| HR Car Sales Ltd | Wholesale & retail | 2026 |
| Hshtc Limited | Professional & scientific | 2002 |
| HTJ Services Ltd | Construction | 2022 |
| Hub Lighting Solutions Limited | Manufacturing | 2012 |
| Hudson Homes and Development Ltd | Construction | 2021 |
| Hudson House Albany Ltd | Real estate | 2020 |
| Hughes Groundworks Limited | Construction | 2008 |
| Hughes International Investments Ltd | Professional & scientific | 2022 |
| Hungry HOG BBQ Ltd | Hospitality | 2017 |
| Hunter & Hunter Group Ltd | Hospitality | 2024 |
| Hupsoo Ltd | Administrative & support | 2025 |
| Hutton (Electrical) Limited | | 1975 |
| Hutton Doors Ltd | Construction | 2019 |
| Hwgc Ltd | Education | 2025 |
| HWH Design and Manufacturing Limited | Manufacturing | 2024 |
| Hydrix Technology Group Ltd | Manufacturing | 2017 |
| Hydro Road Limited | Construction | 2023 |
| Hylands Homes Ltd | Construction | 2015 |
| Hype Branding Holdings Limited | Financial services | 2017 |
| Hype Branding Limited | Administrative & support | 2011 |
| Hype Global Toys Ltd | Manufacturing | 2020 |
| Hype Hair Design Limited | Other services | 2010 |
| Hype Hair Ltd | Other services | 2020 |
| Hytec Construction Limited | Other services | 2016 |
| I & a Windows and Conservatories Limited | Construction | 2014 |
| I D Corcoran Building Contractors Limited | Construction | 1974 |
| I Ford IT Consultancy Limited | Administrative & support | 2025 |
| I Porter Limited | Professional & scientific | 1999 |
| I-Associates (UK) Limited | Other services | 2007 |
| I-Build Construction (South) Ltd | Construction | 2022 |
| I-Cost Ltd | Information & communication | 2015 |
| IAN Croft Limited | Professional & scientific | 2002 |
| IAN Wherry Limited | Arts & recreation | 2008 |
| Ibex Roofing Ltd | Construction | 2025 |
| Ibzz Limited | Hospitality | 2019 |
| Ice Scaffolding & Access Solutions Ltd | Construction | 2026 |
| IDC Greenscapes Limited | Administrative & support | 2003 |
| IDC Survey Solutions Limited | Construction | 2026 |
| Ideal Furniture Importers Ltd | Wholesale & retail | 2018 |
| IGH Services Limited | Transport & logistics | 2015 |
| Ignis Cleaning and Support Services Ltd | Administrative & support | 2018 |
| Ignition Autos (2025) Limited | Extraterritorial | 2018 |
| IJH Training Limited | Professional & scientific | 2023 |
| ILB Carpentry Ltd | Construction | 2025 |
| Ilex & Hedera Limited | Real estate | 2020 |
| Ilir Valeting Limited | Wholesale & retail | 2016 |
| Iliyaz Barbers Ltd | Other services | 2023 |
| Iluminar Ltd | Professional & scientific | 2013 |
| Image Windows & Doors (Essex) Limited | Construction | 2018 |
| Immaculate Complexion Limited | Other services | 2018 |
| Immo Management Ltd | Extraterritorial | 2016 |
| Imperial Calibrations Services Ltd | Professional & scientific | 2023 |
| IN Tune Executive Coaching Limited | Administrative & support | 2021 |
| Indigo Supplies Limited | Wholesale & retail | 2001 |
| Industrial Process Solutions Limited | Professional & scientific | 2020 |
| Infra-Tech Forensics (Audio) Limited | Professional & scientific | 2008 |
| Ingy Investment Cycle Ltd | Financial services | 2018 |
| Initio Services Ltd | Professional & scientific | 2018 |
| Innit Store Ltd | Wholesale & retail | 2022 |
| INNOV8RAIL Ltd | Professional & scientific | 2024 |
| Innovative IT Design Limited | Extraterritorial | 2009 |
| Innvinity Consulting Ltd | Information & communication | 2014 |
| Inovacore Limited | Information & communication | 2014 |
| Inspiration 2 Installation Ltd | Construction | 2018 |
| Inspire EHC Limited | Administrative & support | 2020 |
| Inspire Tutoring Ltd | Extraterritorial | 2026 |
| Integrated Ambulance Solutions Ltd | Professional & scientific | 2024 |
| Intelclear Limited | Transport & logistics | 2025 |