| GIA (Gardening in Action) CIC | Other services | 2022 |
| Girls in Golf Society CIC | Arts & recreation | 2022 |
| Goldstone Signals Limited | Administrative & support | 2015 |
| Good 4 People Ltd. | Wholesale & retail | 2019 |
| Good Life Innovations Ltd | Wholesale & retail | 2009 |
| Goodfood Newhaven Ltd | Hospitality | 2015 |
| Gorrie Consulting Limited | Professional & scientific | 2016 |
| Gover Associates Limited | Professional & scientific | 2006 |
| Green & Gold Wines Ltd | Wholesale & retail | 2018 |
| Green Construction Consultants Limited | Construction | 2025 |
| Greve & SON Ltd | Construction | 2012 |
| Greve Properties Limited | Real estate | 2020 |
| Grime Army Limited | Administrative & support | 2021 |
| Growthenabla Ltd | Information & communication | 2020 |
| H I Brown Ltd | Real estate | 2024 |
| H.Z.E Limited | Hospitality | 2019 |
| Hajavi Ltd | Other services | 2026 |
| Halcyon Recruitment Limited | Administrative & support | 2005 |
| Halo Psychology Ltd | Professional & scientific | 2016 |
| Handyunit Company Limited | Construction | 1992 |
| Harbour View (Duke's Quay) Limited | Households | 2003 |
| Harley House Craft Distillery Ltd | Manufacturing | 2017 |
| Harley House Distillery Ltd | Manufacturing | 2017 |
| Harmonising Leaves Ltd | Hospitality | 2025 |
| Harp Liquor Stores Limited | Wholesale & retail | 1994 |
| Harri Nats Ltd | Hospitality | 2025 |
| Harvey James Accommodation Limited | Hospitality | 2015 |
| Haven Motor Works Ltd | Wholesale & retail | 2025 |
| Haven Properties (Sussex) Limited | Real estate | 2025 |
| Havens & Deans Community Transport | Transport & logistics | 2013 |
| Haygan Limited | Information & communication | 2020 |
| HB Healthcare Services Limited | Health & social care | 2017 |
| Hbinfo Properties (2016) Ltd | Real estate | 2016 |
| HDS Drapes Ltd | Wholesale & retail | 2026 |
| Help Property Management Ltd | Real estate | 2021 |
| Help Squared Ltd | Information & communication | 2025 |
| Heritage Refreshments Limited | Hospitality | 2015 |
| Heritage Woodwork East Sussex Ltd | Manufacturing | 2026 |
| Hgvhelp Ltd | Professional & scientific | 2014 |
| High Pixel Games Ltd | Information & communication | 2025 |
| Hillbrow Health and Wellbeing Limited | Health & social care | 2024 |
| Hills Brothers Ltd. | Construction | 2018 |
| Hillside Sussex Management RTM Company Limited | Households | 2025 |
| Hitemill Limited | Households | 1983 |
| HLN Technical Services Ltd. | Professional & scientific | 2014 |
| HM Wellness Labs Ltd | Wholesale & retail | 2024 |
| Holy COW! Ice Cream Company Limited | Hospitality | 2016 |
| Home Nations Lions Lacrosse Ltd | Arts & recreation | 2020 |
| Homescare Ltd | Health & social care | 2021 |
| Homestead Flints Limited | Construction | 2013 |
| Hometrends (East Sussex) Limited | Construction | 2015 |
| Hooftec Limited | Agriculture & fishing | 2006 |
| Horizon Landscapes (UK) Ltd | Arts & recreation | 2002 |
| Horse's Mouth Communications Ltd | Professional & scientific | 2018 |
| Hot Horse Ltd. | Information & communication | 1999 |
| Hotel Management Systems Ltd | Information & communication | 2023 |
| Housemartins Management Limited | Real estate | 2022 |
| Housemartins Surveyors Limited | Professional & scientific | 2004 |
| Howitt Investments LLP | | 2007 |
| HR 4 Case Management Limited | Administrative & support | 2021 |
| Hughenden Court (Hastings) RTM Company Limited | Households | 2004 |
| Hurricane Cricket Limited | Wholesale & retail | 2014 |
| Husky Events Limited | Professional & scientific | 2010 |
| Hyperlures Limited | Manufacturing | 2017 |
| Hythe Crescent Limited | Extraterritorial | 2023 |
| I Support YOU Limited | Information & communication | 2012 |
| Icarz Ltd | Transport & logistics | 2012 |
| Icreate Places Ltd | Administrative & support | 2025 |
| Ideal Cornice Ltd | Construction | 2015 |
| Ideas & Words Limited | Professional & scientific | 2010 |
| Igadgetfix LLP | | 2019 |
| Imaginarium Lewes CIC | Education | 2024 |
| Impact Opera Ltd | Arts & recreation | 2010 |
| Indigolight Limited | Information & communication | 1994 |
| Indra Care Company Limited | Health & social care | 2014 |
| Intergenerational Opera C.I.C. | Education | 2022 |
| Interior Visions Limited | Construction | 2012 |
| International Warranty Group Limited | Financial services | 2025 |
| Ivan Motors Limited | Wholesale & retail | 2025 |
| J B Architectural Ironmongery Limited | Wholesale & retail | 2005 |
| J B Health & Safety Consultants Ltd | Professional & scientific | 2008 |
| J C Brickwork Ltd | Construction | 2017 |
| J H General Building Limited | Construction | 2012 |
| J Q Property Services Ltd | Construction | 2013 |
| J Torbet Construction Ltd | Construction | 2025 |
| J.K. Pope & Sons Limited | Construction | 1998 |
| Jackson Mews Limited | Real estate | 2005 |
| Jag-Lovers Limited | Administrative & support | 2005 |
| JAN Comley Ltd | Other services | 2007 |
| Jarode Holdings Limited | Real estate | 2026 |
| JAY Mackie & Sons Ltd | Energy | 2017 |
| Jenna Tucker Therapy Limited | Other services | 2025 |
| Jeskar Property Ltd | Real estate | 2025 |
| JF Motors Ltd | Other services | 2010 |
| JH & KB Property Management Ltd | Real estate | 2024 |
| JH Plumbing and Heating Services Ltd | Construction | 2025 |
| JL Properties and Management Ltd | Real estate | 2020 |
| JM Landscaping and Gardening Limited | Administrative & support | 2020 |
| JMC3 Design Ltd | Administrative & support | 2015 |
| JN Accounting Services Ltd | Professional & scientific | 2005 |