| H.D.Steele and SON (Teville) Limited | Wholesale & retail | 1946 |
| H.I.R. Design Limited | Administrative & support | 2013 |
| H.S.P Management Consultancy Limited | Professional & scientific | 2014 |
| H2O.TO.HEAT Ltd | Construction | 2024 |
| HA (Sussex) Limited | Real estate | 2006 |
| Habitat Living Ltd | Real estate | 2025 |
| Hackinvest Limited | Construction | 2017 |
| Hackney Girl Productions Ltd | Information & communication | 2022 |
| Hackney Media Limited | Information & communication | 2019 |
| Hadley Green Ltd | Real estate | 2021 |
| Hadyn Williams Limited | Information & communication | 2015 |
| Haggeruns Limited | Administrative & support | 2014 |
| HAI Locations Limited | Professional & scientific | 2020 |
| Hair Room (Sussex) Limited | Other services | 2016 |
| Hairsginger IT Ltd | Professional & scientific | 2025 |
| Hairways Barber Shop Ferring Limited | Other services | 2003 |
| Hairways Barbershop Rustington Limited | Other services | 2018 |
| Hairways Studios Limited | Other services | 2018 |
| Halcyon Accounting Services Ltd | Professional & scientific | 2021 |
| Halcyon Estates Ltd | Real estate | 2025 |
| Halcyon Glow Beauty Limited | Other services | 2025 |
| Half Brick Developments Limited | Real estate | 2013 |
| Half-Time Orange Theatre CIC | Arts & recreation | 2022 |
| Halfwine Limited | Wholesale & retail | 2010 |
| Hall's Cleaning Service Ltd | Administrative & support | 2019 |
| Halligan Management Consultants Ltd | Professional & scientific | 2013 |
| Halls of Valhalla Limited | Hospitality | 2024 |
| HAM Way Property Management Ltd | Real estate | 2016 |
| Hamels Mansion Management Ltd. | Households | 2015 |
| Hami Restaurant Ltd | Hospitality | 2026 |
| Hammer Engine Solutions Ltd | Wholesale & retail | 2023 |
| Hammersmith Medicines Research (Properties) Limited | Real estate | 2014 |
| Hammond Concrete Testing & Services Limited | Administrative & support | 1985 |
| Hampshire Sussex Hospitality Co. Ltd | Hospitality | 2025 |
| Hampton Court Worthing Limited | Households | 2022 |
| Hamsterjam Productions Ltd | Arts & recreation | 2016 |
| Hanatek Services Limited | Administrative & support | 2006 |
| Handy Manager Limited | Other services | 2020 |
| Handy-Hubby Limited | Construction | 2004 |
| Handyman South Coast Limited | Construction | 2012 |
| Handymatt Property Maintenance Limited | Other services | 2009 |
| Hangleton Limited | Extraterritorial | 2018 |
| Hanhar Resources Limited | Administrative & support | 2004 |
| Hannaford & Sons Ltd | Construction | 2024 |
| Hannah Payne SEM Services Ltd | Professional & scientific | 2025 |
| Hannah Pindell Design Limited | Professional & scientific | 2016 |
| Hanover Construction Ltd | Construction | 2024 |
| Happy Learners Day Nursery Ltd | Education | 2022 |
| Happy Steps Nursery Limited | Education | 2016 |
| Harbour View Developments (Sussex) Ltd | Construction | 2005 |
| Harcourt Hotels (UK) Limited | Extraterritorial | 1997 |
| Hardiflon Ltd | Administrative & support | 2006 |
| Hardigroup Limited | Administrative & support | 2016 |
| Hardigroup USA Limited | Administrative & support | 2016 |
| Hardings Bar & Catering Services Limited | Hospitality | 1999 |
| Hardy Property Management (South) Limited | Real estate | 2022 |
| Hare & Stone Surfaces Ltd | Construction | 2026 |
| Hare-Stanley Consulting Ltd | Professional & scientific | 2018 |
| Harewood Productions Ltd | Information & communication | 2025 |
| Hargan Estates Ltd | Real estate | 2011 |
| Hargan Passive Ltd | Real estate | 2019 |
| Harla Media Limited | Professional & scientific | 2023 |
| Harlington Homes Investments Limited | Real estate | 2021 |
| Harlington Homes Limited | Construction | 2003 |
| Harlington Land Ltd | Real estate | 2026 |
| Harman Building & Carpentry Ltd | Construction | 2013 |
| Harmless Drudge Limited | Information & communication | 2023 |
| Harpenden Home Developments Ltd | Construction | 2008 |
| Harper Investments GBR Ltd | Real estate | 2025 |
| Harris Electrical Solutions Ltd | Construction | 2020 |
| Harris-Fynes Property Holding Ltd | Real estate | 2026 |
| Harrison Court RTM Company Ltd | Households | 2012 |
| Harrison Hospitalty Ltd | Hospitality | 2015 |
| Harry Jackson Company Limited | Administrative & support | 2004 |
| Harry Smyth Property Ltd | Real estate | 2022 |
| Harthill-Rose Ltd | Professional & scientific | 2024 |
| Hartland House (Worthing) Management Company Limited | Hospitality | 2002 |
| Harts & Minds Limited | Administrative & support | 2008 |
| Harvey Jacob Limited | Administrative & support | 2007 |
| Harwood House Investments Ltd | Real estate | 2020 |
| Hastings Court Management Co. (Worthing) Limited | Households | 1989 |
| Hatch Ideas World Wide Ltd | Other services | 2017 |
| Hatcha Properties Ltd | Real estate | 2024 |
| HATTER1962 Limited | Professional & scientific | 2024 |
| Haulkham Properties Limited | Real estate | 2025 |
| Haulkham Roofing Ltd | Construction | 2026 |
| Haus Folio Ltd | Construction | 2020 |
| Hausai Ltd | Professional & scientific | 2025 |
| Haven House Investments Limited | Real estate | 2000 |
| Havens Group Ltd | Hospitality | 2025 |
| Havercroft Nominees Limited | Professional & scientific | 1989 |
| Hawa Props 11A Ltd | Real estate | 2021 |
| Hawk Aviation Management Limited | Professional & scientific | 2012 |
| Hawker Park Limited | Wholesale & retail | 2010 |
| Hawkeye Pictures Limited | Information & communication | 2012 |
| Hawkins Watts Holdings Ltd | Financial services | 2022 |
| Hawkwood Carpentry Ltd | Manufacturing | 2019 |
| Hayes Warren Properties LLP | | 2016 |
| Hayeswood Creations Limited | Manufacturing | 2024 |
| Hayling Rise Management Company Limited | Real estate | 2010 |