| GSS Limited | Real estate | 1962 |
| GSS Management Ltd | Administrative & support | 2023 |
| GT Electrical Contracts Ltd | Construction | 2025 |
| GT69 Limited | Wholesale & retail | 2020 |
| GTM Search Ltd | Administrative & support | 2022 |
| GTS Joy Services Ltd | Transport & logistics | 2026 |
| GTW Project Management Ltd | Professional & scientific | 2019 |
| GU Tuning Files Ltd | Information & communication | 2024 |
| Guardforce Security Limited | Administrative & support | 2002 |
| Guardforce Security Services (UK) Ltd | Administrative & support | 2006 |
| Guardian Archive Limited | Arts & recreation | 1997 |
| Guardian Desktop Solutions Ltd | Financial services | 2026 |
| Guardian Group Limited | Wholesale & retail | 2019 |
| Guardian Roofing & Building Limited | Construction | 2025 |
| Guardian Secure Storage Limited | Other services | 2003 |
| Guerdon Metier Limited | Professional & scientific | 1994 |
| Guerin Estates and Investments Limited | Real estate | 2016 |
| Guia Investments Limited | Construction | 1992 |
| Guia Limited | Construction | 2011 |
| Guidelineroofing Ltd | Construction | 2026 |
| Guildford Lodge Management Company Limited | Households | 1984 |
| Guilt Free Music Publishing Ltd | Information & communication | 2013 |
| Guilt Free Post Limited | Information & communication | 2010 |
| GUN Cricket Ltd | Wholesale & retail | 2021 |
| GUN Hill 1 Limited | Professional & scientific | 2025 |
| GUN Hill 2 Limited | Construction | 2025 |
| Gunfleet Developments Ltd | Construction | 2025 |
| Gunfleet Sands Fisheries Fund Limited | Agriculture & fishing | 2008 |
| Gunnett Digger Hire Ltd | Construction | 2015 |
| Gunsmoke Paintball Limited | Arts & recreation | 2007 |
| Gurkha Lauree Ltd | Wholesale & retail | 2020 |
| Gurkha Lounge Colchester Limited | Hospitality | 2024 |
| Gurkha Stores Ltd | Wholesale & retail | 2023 |
| Gurleys Ltd | Public administration | 2022 |
| Guru Circus Limited | Administrative & support | 2014 |
| Gurukul-Uk CIC | Public administration | 2022 |
| GUT UK Service Limited | Health & social care | 2017 |
| Gutter Supplies Ltd | Extraterritorial | 2008 |
| Guttering Doctor Limited | Extraterritorial | 2013 |
| Gutvio Ltd | Wholesale & retail | 2020 |
| GUY Swan Limited | Construction | 2000 |
| Guyon & Sons Ltd | Construction | 2010 |
| Guysfield House Limited | Health & social care | 2001 |
| Gvk&Pt PVT Ltd | Wholesale & retail | 2023 |
| GVZ Glasshouses (Holdings) Limited | Real estate | 1986 |
| GVZ Glasshouses Limited | Construction | 2010 |
| GW GEO Ltd | Professional & scientific | 2026 |
| GW Transport Solutions Limited | Transport & logistics | 2015 |
| GW23 Ltd | Real estate | 2023 |
| GWJ Contracts Limited | Wholesale & retail | 2015 |
| Gyantech Ltd | Manufacturing | 2026 |
| Gyles & Rose Lettings Limited | Real estate | 2022 |
| Gyles & Rose Limited | Real estate | 2020 |
| Gym Leaders Ltd | Professional & scientific | 2023 |
| Gym Mastery Ltd | Professional & scientific | 2023 |
| Gymophobics (Colchester) Limited | Arts & recreation | 2006 |
| Gymos Ltd | Information & communication | 2025 |
| Gypsy Pirates Limited | Wholesale & retail | 2016 |
| Gyrus Olympic Gymnastics Club | Arts & recreation | 2012 |
| H & H Developments (Essex) Ltd | Construction | 2010 |
| H & R Strood Contracts Limited | Administrative & support | 1988 |
| H & V Dental Ltd | Health & social care | 2017 |
| H B Tendering Limited | Hospitality | 2025 |
| H D Consultants Ltd | Financial services | 2003 |
| H D Roofing & Cladding Ltd | Construction | 2020 |
| H Griffith Sealants Limited | Construction | 2021 |
| H H Entertainment Ltd | Professional & scientific | 2019 |
| H M Chimney Sweeping Limited | Administrative & support | 2011 |
| H RIX Properties Limited | Real estate | 2019 |
| H&J London Ltd | Transport & logistics | 2016 |
| H&P Property Investments Ltd | Real estate | 2020 |
| H&R Leisure Limited | Hospitality | 2025 |
| H&S Solutions Limited | Administrative & support | 2013 |
| H&T Elevate Ltd | Health & social care | 2024 |
| H.& E.Edwards(Colchester)Limited | Wholesale & retail | 1962 |
| H.B.C. Developments Limited | Construction | 1997 |
| H.C.Percival (Farms) Limited | Agriculture & fishing | 1953 |
| H.Clark (Farmers) Limited | Wholesale & retail | 1962 |
| H.D. Blyth Limited | Professional & scientific | 1995 |
| H.E.L.P. Management Services Limited | Health & social care | 2009 |
| H.F. Bond and Co Limited | Manufacturing | 1978 |
| H.J.B. Commercials Limited | Other services | 1996 |
| H.W. Andersen Products Limited | Health & social care | 1973 |
| H.W. Bone and Co UK Ltd | Real estate | 2010 |
| H.W.Bone & Co.,Limited | Professional & scientific | 1951 |
| H.Wood Electrical Services Ltd | Construction | 2018 |
| H2 Cortex Ltd | Information & communication | 2026 |
| H2 Gambling Capital Limited | Information & communication | 2016 |
| H2 Holdco 2 Limited | Financial services | 2024 |
| H2 Management Limited | Professional & scientific | 2017 |
| H2 North America Limited | Information & communication | 2023 |
| H2 Premium Limited | Administrative & support | 2023 |
| H20 (East Street) Limited | Households | 2004 |
| H2O Systems Ltd | Water & waste | 2021 |
| Haart Limited | Real estate | 1986 |
| Habdale Limited | Other services | 1985 |
| Habeg Consult Limited | Real estate | 2022 |
| Habico Developments Ltd | Construction | 2022 |
| Habico Homes Ltd | Hospitality | 2019 |
| Hace Holdings Limited | Financial services | 2021 |