| Halcyon Hairdressing Ltd | Other services | 2013 |
| Halley Court Limited | Households | 2008 |
| Hambery Residents Association Limited | Households | 1991 |
| Hampden Park Motoring Centre Ltd | Wholesale & retail | 2025 |
| HAN GUK MU Sool Ltd | Arts & recreation | 2023 |
| Hancock Creative Limited | Other services | 2021 |
| HANDS-ON57 Limited | Health & social care | 2013 |
| Handson Relocations Ltd | Extraterritorial | 2023 |
| Hanover Gate Mansions Limited | Households | 2003 |
| Hanover Gate Mansions Property Management (Blocks 1 to 3) Ltd | Households | 1975 |
| Hanover Gate Mansions Property Management (Blocks 4 to 6) Ltd | Households | 1973 |
| Hard Surface Heroes Ltd | Construction | 2025 |
| Hardhat Trade Solutions Ltd | Administrative & support | 2025 |
| Harrison Goodness Foundation | Extraterritorial | 2011 |
| Harrisons Pubs Ltd | Hospitality | 2025 |
| Harwood Heights Management Limited | Households | 2016 |
| Hasbik Limited | Hospitality | 2026 |
| Hasting Kebab Ltd | Hospitality | 2024 |
| Hastings Advice and Representation Centre | Health & social care | 2000 |
| Hastings and Rother Healthcare 2 Ltd | Real estate | 2024 |
| Hastings Arts Forum Ltd | Arts & recreation | 2011 |
| Hastings Badger Protection Society | Professional & scientific | 2015 |
| Hastings Cloud Ltd | Information & communication | 2019 |
| Hastings Couriers Limited | Transport & logistics | 2020 |
| Hastings Embroidery Limited | Wholesale & retail | 2002 |
| Hastings Energy Limited | Professional & scientific | 2014 |
| Hastings Fencing and Landscaping Limited | Administrative & support | 2023 |
| Hastings Fencing Ltd | Construction | 2021 |
| Hastings Garage Door and Gate Systems Ltd | Construction | 2025 |
| Hastings IT Support Limited | Information & communication | 2026 |
| Hastings Kids Collective C.I.C. | Health & social care | 2024 |
| Hastings Online Times CIC | Information & communication | 2018 |
| Hastings Property Holdings Ltd | Real estate | 2021 |
| Hastings Property Services Ltd | Real estate | 2020 |
| Hastings Scaffold UK Ltd | Construction | 2017 |
| Hastings Sport CIC | Arts & recreation | 2015 |
| Haus of Edit Limited | Wholesale & retail | 2025 |
| Hawker Property Maintenance Limited | Other services | 2014 |
| Hawklee Ltd | Hospitality | 2022 |
| Hdjs Management Ltd | Households | 2023 |
| Heart Editions Limited | Extraterritorial | 2001 |
| Helia Renewables Limited | Construction | 2022 |
| Hello Polly Copywriters Limited | Professional & scientific | 2022 |
| Heritage Connections Limited | Information & communication | 2025 |
| Heron Court Management Company (East Sussex) Limited | Real estate | 2004 |
| Herstmonceux Pre-School Limited | Education | 2017 |
| Hibanana Ltd | Wholesale & retail | 2019 |
| High Beech Estate Ltd | Real estate | 2023 |
| High Beech Estate Management Ltd | Real estate | 2024 |
| Highfield House Lewes RTM Company Ltd | Households | 2021 |
| Highkiln RTM Company Limited | Households | 2022 |
| Highland Suite Limited | Households | 2007 |
| Hjsbreaks Ltd | Wholesale & retail | 2025 |
| HK Barber Hastings Limited | Other services | 2025 |
| HK Garden Inn Limited | Hospitality | 2021 |
| Hktr Properties Ltd | Real estate | 2026 |
| Hokus Pokus Ltd | Real estate | 2021 |
| Hole Projects CIC | Arts & recreation | 2025 |
| Holland House (ST. Leonards) Residents Limited | Hospitality | 1995 |
| Holly Blakeley Hair Ltd | Other services | 2022 |
| Home Live Art Limited | Arts & recreation | 2005 |
| Homeflower UK Ltd | Wholesale & retail | 2026 |
| Honeycomb Cakes Limited | Manufacturing | 2012 |
| Hopper Electrical Services Limited | Construction | 2025 |
| Horizon Hove Limited | Households | 2006 |
| Hosain Management Consultancy Ltd | Professional & scientific | 2014 |
| House of Hedencrona Ltd | Professional & scientific | 2024 |
| House of Icons Entertainment Ltd | Administrative & support | 2021 |
| Housemonkey Limited | Information & communication | 2011 |
| Hove Lawns Properties Limited | Households | 1980 |
| HPH (SE) Limited | Water & waste | 2025 |
| Humble Seafood Ltd | Hospitality | 2021 |
| Hunter Close Protection Ltd | Administrative & support | 2026 |
| Hwxyz Limited | Real estate | 2025 |
| Hyland Consultants LLP | | 2008 |
| I-Jam Media Limited | Professional & scientific | 2014 |
| Iamgate Limited | Information & communication | 2024 |
| Iatanaso Ltd | Professional & scientific | 2026 |
| Ibanes Sport Limited | Wholesale & retail | 2019 |
| Iberian Lighting Ltd. | Manufacturing | 2003 |
| Iborn Designs Ltd | Professional & scientific | 2025 |
| IBS21 Ltd | Construction | 2020 |
| Icocc Limited | Wholesale & retail | 2014 |
| IDL Limited | Information & communication | 1984 |
| IDS Industries Limited | Agriculture & fishing | 2024 |
| IFA TEK Limited | Professional & scientific | 2002 |
| Ilikhan Ltd | Hospitality | 2019 |
| Ilsenk Traders Limited | Real estate | 2023 |
| Immac Cleaningservices Ltd | Manufacturing | 2026 |
| Immure Productions Ltd | Information & communication | 2010 |
| Ince Consultancy Limited | Administrative & support | 2026 |
| Initiative Digital Services Ltd | Professional & scientific | 2026 |
| Inktron Design Ltd | Professional & scientific | 2025 |
| Innoval Design Limited | Manufacturing | 2022 |
| Innovation Finance Limited | Financial services | 2010 |
| Inspirante Online Academy Ltd | Education | 2026 |
| Inspired Property Lettings (Sussex) Limited | Households | 2023 |
| Instrument Technology Limited | Manufacturing | 2005 |
| Integra Construction Limited | Administrative & support | 2018 |
| Interface Con-X Ltd | Information & communication | 1987 |