| Grove Estates & Developments Limited | Construction | 2004 |
| Grove Mansions (Abergavenny) Limited | Households | 2005 |
| Growth & Impact Ltd | Professional & scientific | 2019 |
| Grwyne Fawr C.I.C. | Other services | 2015 |
| Gurkha Corner Restaurant a Ltd | Hospitality | 2013 |
| Guru Gift Gallery & Repair Limited | Manufacturing | 2024 |
| Gwagle Space Ltd | Real estate | 2019 |
| GWC Ironmongery Ltd | Wholesale & retail | 2020 |
| Gwent Ltd | Real estate | 2024 |
| Gwent Studios Ltd | Information & communication | 2025 |
| GÜT Beer Ltd | Manufacturing | 2025 |
| H Bufton Limited | Construction | 2025 |
| H Shackleton (Holdings) Limited | Financial services | 2017 |
| H.D. Davies Boats Limited | Administrative & support | 2008 |
| H.E.Farr Ltd | Health & social care | 2018 |
| H2D2O Limited | Professional & scientific | 2018 |
| Hamilton Milnes Ltd | Hospitality | 2019 |
| Hampton Printing (Europe) Limited | Manufacturing | 2016 |
| Hamro Tanglewood Ltd | Hospitality | 2022 |
| Handprint Production Ltd | Manufacturing | 2022 |
| Happy Dragons Theatre CIC | Arts & recreation | 2025 |
| Happy Homes Cleaning Services Limited | Administrative & support | 2023 |
| Hareandmoonpilates Ltd | Other services | 2026 |
| Harhion Homes Ltd | Construction | 2022 |
| Harold Developments Ltd | Information & communication | 2026 |
| Harpers Pmconsultancy Ltd | Professional & scientific | 2021 |
| Harpers Property Services Ltd | Real estate | 2023 |
| Harrhy Carpets and Beds Limited | Wholesale & retail | 2016 |
| Harry & Myrtle Limited | Manufacturing | 2022 |
| Haslett Properties Limited | Real estate | 2022 |
| Hatcher Harris Ltd | Education | 2024 |
| Haven Land and Property Ltd | Real estate | 2024 |
| Hawksdrift Limited | Agriculture & fishing | 2011 |
| Haxby Court (Cardiff) Management Company Limited | Households | 2005 |
| Hayes Bridgland Ltd | Arts & recreation | 2013 |
| HB Podiatry Limited | Health & social care | 2022 |
| HD Electrical and Renewables Ltd | Construction | 2022 |
| Heads of the Valleys Training Ltd | Education | 2018 |
| Health Psychology Wales Ltd | Real estate | 2003 |
| Hearing Express Ltd | Extraterritorial | 1997 |
| Heart Spring Community CIC | Other services | 2025 |
| Heidi Homes Ltd | Real estate | 2019 |
| Height Studio Limited | Professional & scientific | 2012 |
| Helen Marks Marketing Limited | Professional & scientific | 2001 |
| Helfare Ltd | Wholesale & retail | 2020 |
| Helyg Crafts Limited | Agriculture & fishing | 2021 |
| Helyg Tree Surveys Ltd | Agriculture & fishing | 2021 |
| HEN Clawdd Flats Management Company Limited | Households | 2023 |
| Hendre Distillery Ltd | Manufacturing | 2018 |
| Hendre Glyn Biomass Limited | Agriculture & fishing | 2014 |
| Hendre Glyn Events Ltd | Administrative & support | 2024 |
| Hendre Glyn Property Management Limited | Hospitality | 2017 |
| Hereford Sushi Ltd | Hospitality | 2025 |
| Heritage Frozen Foods Limited | Hospitality | 2014 |
| Heritage Motor Works Limited | Manufacturing | 2003 |
| Heronhurst Holdings Limited | Manufacturing | 1983 |
| Heronhurst Window & Door Centre Limited | Manufacturing | 2004 |
| Heuris Limited | Information & communication | 2025 |
| Hideout Homes Ltd | Real estate | 2020 |
| Hikr Ltd | Wholesale & retail | 2025 |
| Hilarys Flowers Limited | Wholesale & retail | 2011 |
| Hill ASH Court Management Ltd | Real estate | 2024 |
| Hill ASH Investments Ltd | Real estate | 2024 |
| Holevy Consultants Limited | Professional & scientific | 1995 |
| Holley Automation Ltd | Administrative & support | 2021 |
| Holly Financial Ltd | Financial services | 2021 |
| Holm Oak Homes (Whitfield Court) Ltd | Construction | 2019 |
| Holm Oak Projects Limited | Construction | 2003 |
| Home County Homes Ltd | Real estate | 2024 |
| Homemakers Community Recycling | Water & waste | 2002 |
| Homes by Butler Ltd | Real estate | 2025 |
| Homeward Ltd | Real estate | 2020 |
| Honeycomb Print Services Ltd | Manufacturing | 2013 |
| Hoole Studio Ltd | Professional & scientific | 2014 |
| Hopgrove Construction Ltd | Construction | 2020 |
| Hopgrove Developments Ltd | Construction | 2021 |
| House of Morris Limited | Real estate | 2024 |
| HRM Renovations Ltd | Construction | 2023 |
| Hulme Aerospace Consultants Ltd | Professional & scientific | 2025 |
| Hummadruz C.I.C. | Arts & recreation | 2015 |
| Hummingbird Celebrants Ltd | Other services | 2023 |
| IAM Financial Services Ltd | Financial services | 2010 |
| IAN Turner Farm Supplies Limited | Wholesale & retail | 2020 |
| Ikaria Developments Limited | Construction | 2018 |
| Ikaria Lifestyle Limited | Construction | 2018 |
| Ikdv Solutions Limited | Information & communication | 2013 |
| Improv Stars Academy Ltd | Arts & recreation | 2025 |
| Inari Wealth Management Limited | Administrative & support | 2016 |
| Indigo Project Management Limited | Professional & scientific | 1998 |
| Industrial Cleaning Services Carver Plant Limited | Administrative & support | 2023 |
| Inexium International Limited | Professional & scientific | 2024 |
| Infinity Fence Ltd | Construction | 2025 |
| Intelec Solar and Electrical Ltd | Energy | 2025 |
| Intelligent Cyber Solutions Limited | Information & communication | 2016 |
| Intelligent Transportation Systems Limited | Transport & logistics | 2018 |
| Ipearl Solutions Ltd | Wholesale & retail | 2012 |
| Ipearl Tech Solutions Ltd | Wholesale & retail | 2015 |
| Irving-Stewart Limited | Real estate | 1937 |
| Ivie Garden Ltd | Health & social care | 2022 |
| Izzet Catering Limited | Hospitality | 2020 |