| H and R Hall Ltd | Wholesale & retail | 2015 |
| H D J Services Ltd | Wholesale & retail | 2023 |
| H Dean Property Ltd | Real estate | 2017 |
| H E Tyres Ltd | Wholesale & retail | 2021 |
| H F L Management Company Limited | Households | 2007 |
| H G Long Property Limited | Real estate | 2016 |
| H L Property Developers Ltd | Construction | 2022 |
| H S Optical Limited | Real estate | 1998 |
| H&A Homes Limited | Real estate | 2021 |
| H&H Swindon Ltd | Hospitality | 2022 |
| H&M Partners Limited | Administrative & support | 1991 |
| H&S Driveways & Landscaping Ltd | Construction | 2025 |
| H&S Walcot Barbers Ltd | Other services | 2023 |
| H&W Entertainment Ltd | Hospitality | 2025 |
| H. Hibberd Limited | Construction | 1961 |
| H.C.T. Services Ltd | Professional & scientific | 2002 |
| H.G. Hanks Limited | Wholesale & retail | 1954 |
| H.G.H. Associates Limited | Administrative & support | 1999 |
| H.L.Sainsbury & Sons Limited | Agriculture & fishing | 1961 |
| H.M.S. Racing Ltd | Administrative & support | 2012 |
| H2H Renovations Ltd | Real estate | 2025 |
| H2O Cleaning Ltd | Administrative & support | 2005 |
| H4 Alpha Properties Ltd | Construction | 2026 |
| H5 Adventure Ltd | Arts & recreation | 2006 |
| H95 Administration Limited | Public administration | 2019 |
| Haamed Ltd | Health & social care | 2022 |
| Habitat Solutions (Swindon) Limited | Construction | 2014 |
| Habitect Developments Ltd | Construction | 2017 |
| Habitect Holdings Ltd | Financial services | 2017 |
| Habl Ltd | Hospitality | 2021 |
| Habs Consultancy Ltd | Hospitality | 2011 |
| Hacharl Health Ltd | Health & social care | 2020 |
| Hacketthealthcare Limited | Health & social care | 2019 |
| Hackpen White Horse Limited | Professional & scientific | 2022 |
| HAD Digital Ltd | Professional & scientific | 2021 |
| Hadebe Goods Ltd | Wholesale & retail | 2026 |
| Haemonetics Africa UK Ltd | Construction | 2025 |
| HAH Consulting Ltd | Professional & scientific | 2018 |
| Hailstone Productions Limited | Administrative & support | 2017 |
| Haines Watts Business Advisory Limited | Professional & scientific | 2026 |
| Haines Watts Cardiff Limited | Professional & scientific | 2025 |
| Haines Watts Cirencester Limited | Professional & scientific | 2020 |
| Haines Watts Limited | Professional & scientific | 1987 |
| Haines Watts Swindon (Services) Limited | Professional & scientific | 2024 |
| Haines Watts Swindon Limited | Professional & scientific | 2024 |
| Hair Candie Ltd | Other services | 2019 |
| Hair R US Ltd | Wholesale & retail | 2025 |
| Hair Studio (Maidenhead) Limited | Other services | 2014 |
| Haircare (Swindon) Limited | Other services | 2005 |
| Hakka 2 Limited | Hospitality | 2022 |
| Halcyon Leadership Ltd | Information & communication | 2023 |
| Halcyon MYC Ltd | Hospitality | 2020 |
| Hale Associates Limited | Agriculture & fishing | 2002 |
| Haley Consulting Limited | Information & communication | 2011 |
| Haligspring Pharma Consulting Limited | Professional & scientific | 2023 |
| Hall Homes (Contracting) Limited | Construction | 2007 |
| Hallen Logistics Ltd | Transport & logistics | 2016 |
| Hallmarque Group Ltd | Wholesale & retail | 2019 |
| Halo Windows Swindon Limited | Construction | 2019 |
| Haltadel Limited | Health & social care | 2017 |
| Haltipop Properties Ltd | Construction | 2026 |
| Halzac Design Limited | Professional & scientific | 2008 |
| Hamals Homes Limited | Construction | 2022 |
| Hamals Homes Property Ltd | Real estate | 2025 |
| Hamba Lapa Ltd | Mining & quarrying | 2026 |
| Hamdanbash Ltd | Information & communication | 2022 |
| Hamilton Grace Limited | Hospitality | 2015 |
| Hammer Furniture Limited | Manufacturing | 2025 |
| Hammersley Developments Limited | Construction | 2022 |
| Hampal Limited | Wholesale & retail | 2021 |
| Hanbury Developments Limited | Construction | 1996 |
| Hancis Ltd | Other services | 2025 |
| Hand Picked Motors Swindon Ltd | Wholesale & retail | 2021 |
| Handbook Digital Limited | Information & communication | 2022 |
| Handel Group Limited | Financial services | 2022 |
| Handel Online Limited | Wholesale & retail | 2025 |
| Handyservices 4 U Limited | Construction | 2009 |
| Hanefa Ltd | Hospitality | 2024 |
| Hanifi Properties Ltd | Real estate | 2024 |
| Hanison Commercial Management (UK) Limited | Professional & scientific | 2012 |
| Hanison Group (Holdings) Limited | Financial services | 2018 |
| Hanlex Holdings Ltd | Real estate | 2024 |
| Hanmers Consulting Limited | Information & communication | 2015 |
| Hannah Mcdanielson Jewellery Limited | Manufacturing | 2026 |
| Hannick Developments Limited | Construction | 2024 |
| Hannick Holdings Limited | Financial services | 1993 |
| Hanrahan Developments Ltd | Construction | 2014 |
| Hanuma Solutions Limited | Information & communication | 2015 |
| Hapg Consulting Ltd | Professional & scientific | 2025 |
| Happiness LAB Limited | Professional & scientific | 2010 |
| Happy Camper Products Ltd | Wholesale & retail | 2019 |
| Happy Cleaning 4 YOU Ltd | Administrative & support | 2024 |
| Happy Construction & Maintenance Ltd | Construction | 2025 |
| Happy Cook Chinese Takeaway Ltd | Hospitality | 2019 |
| Happy Escapes Ltd | Hospitality | 2023 |
| Happy Glastonbury Limited | Wholesale & retail | 2010 |
| Happy Home and Garden Ltd | Construction | 2023 |
| Happy Life Homes Ltd | Real estate | 2021 |
| Happy Monkey Ltd | Wholesale & retail | 2021 |
| Happy Stays Wiltshire Ltd | Hospitality | 2024 |