| Grooming Doggy Style Ltd | Other services | 2023 |
| Grounded Property Limited | Real estate | 2025 |
| Groundsforgooduk Ltd | Wholesale & retail | 2021 |
| Grove Corporation Ltd | Wholesale & retail | 2026 |
| Grove Surgery Ltd | Health & social care | 2014 |
| Grovesmed Limited | Health & social care | 2024 |
| GSN Property Holdings Limited | Construction | 2020 |
| GTB Management Services Ltd | Construction | 2023 |
| Gutter Kleanz (Wales) Limited | Administrative & support | 2018 |
| GWE Enterprise Park Ltd | Real estate | 2026 |
| Gwenfo ECM Ltd | Professional & scientific | 2023 |
| Gwentland Drive Limited | Households | 2022 |
| Gwernllan Ltd | Construction | 2018 |
| Gwernos Limited | Construction | 2020 |
| Gwpb Limited | Professional & scientific | 2022 |
| Gwyn Properties Limited | Real estate | 2010 |
| Gym-Stuff Ltd | Wholesale & retail | 2015 |
| H & J Curtin Property Ltd | Real estate | 2025 |
| H & S Electrical Ltd | Extraterritorial | 2023 |
| H R Bespoke Ltd | Wholesale & retail | 2020 |
| H R Properties (Cardiff) Ltd | Real estate | 2016 |
| H&T Property Group Ltd | Real estate | 2026 |
| H.L.J Carpentry Ltd | Manufacturing | 2022 |
| Haddon Advisory Limited | Professional & scientific | 2025 |
| Hadis Properties Ltd | Real estate | 2019 |
| Hair OR Make UP Limited | Other services | 2013 |
| Hallaran Health and Safety Compliance Limited | Other services | 2017 |
| Halliard Court Ltd. | Real estate | 1995 |
| Hallswood Aero Services Limited | Professional & scientific | 2026 |
| Hamptons Penarth Ltd | Wholesale & retail | 2015 |
| Hardie Home Improvements Ltd | Construction | 2023 |
| Harlequin Agency Limited | Administrative & support | 1986 |
| Harlin Investments Limited | Real estate | 2006 |
| Harries Financial Wealth Management Ltd | Financial services | 2019 |
| Harries Homes Limited | Real estate | 2024 |
| Harries, Powell & Price Ltd. | Financial services | 2012 |
| Harriet Pierpoint Consulting Ltd | Professional & scientific | 2025 |
| Harris Construction (Penarth) Ltd | Construction | 2014 |
| Harris John Property Limited | Real estate | 2015 |
| Harvest Agency Services Limited | Transport & logistics | 2001 |
| Harvest Chartering Services Limited | Transport & logistics | 2000 |
| Harvest Cymru Group Limited | Financial services | 2019 |
| Hawkins Evans Property Ltd | Real estate | 2020 |
| Hawkins Homes Investments Limited | Real estate | 2017 |
| Hawkins Investment Properties Ltd | Construction | 2025 |
| Hawthorn Gardens Management (Caerleon) Limited | Households | 1996 |
| Hayward Productions Ltd | Other services | 2020 |
| Hdjones Ltd | Hospitality | 2024 |
| Healey Bespoke Interiors Ltd | Construction | 2026 |
| Health by Heart Ltd | Education | 2024 |
| Hear Solutions Ltd | Professional & scientific | 2021 |
| Heath Motor Co. (Properties) Ltd. | Real estate | 2003 |
| Hedd CYF | Arts & recreation | 2025 |
| Henw Ltd | Administrative & support | 2025 |
| Heol HIR (Cardiff) Management Company Limited | Administrative & support | 2008 |
| Herwebsolutions Limited | Information & communication | 2024 |
| HGJ Consultancy Ltd | Professional & scientific | 2025 |
| HI View Scaffolding Cardiff Limited | Construction | 2023 |
| Hidden Records Ltd | Information & communication | 2026 |
| Highfield Close Management Limited | Households | 1982 |
| Highlands (Penarth) Limited | Real estate | 2018 |
| Highlands (Penarth) Management Limited | Households | 2019 |
| Hillman & Harris Property Development Ltd | Construction | 2019 |
| Hina News Limited | Wholesale & retail | 2001 |
| Hintonmarsh Limited | Hospitality | 1993 |
| Hodder Homes Ltd | Real estate | 2025 |
| Holder Healthcare Recruitment Ltd | Administrative & support | 2025 |
| Holestone Ltd | Real estate | 2018 |
| Holmes Marine Parade (Maintenance) Limited(The) | Households | 1985 |
| Holmes Property Investments Ltd | Construction | 2014 |
| Holms Court (Sully) Management Company Limited | Households | 2012 |
| Home Access - Tabernacle Baptist Church | Health & social care | 1996 |
| Home at Penarth Ltd | Hospitality | 2020 |
| Home Inspector 4 Hips Limited | Administrative & support | 2007 |
| Homer-Forbes International Limited | Professional & scientific | 2012 |
| Homerite Bathrooms Limited | Wholesale & retail | 2019 |
| Homeside House RTM Company Limited | Households | 2024 |
| Homewise Conveyancing Services Limited | Professional & scientific | 1989 |
| Honey to the Brie Limited | Extraterritorial | 2018 |
| Horizon (Whitchurch) Management Company Limited | Households | 2006 |
| House of Bread (Barry) Ltd | Wholesale & retail | 2025 |
| HP (One) RTM Company Limited | Households | 2016 |
| HP (Three) RTM Company Limited | Households | 2016 |
| HP (Two) RTM Company Limited | Households | 2016 |
| Hugh Collier Ltd | Information & communication | 2026 |
| Hugo Souto Building and Refurbishments Limited | Construction | 2021 |
| Hugo Souto Homes Limited | Real estate | 2021 |
| Hurts SO Good Murals Ltd | Wholesale & retail | 2025 |
| Hurts SO Good UK CIC | Arts & recreation | 2024 |
| Hutano Hwedu Limited | Health & social care | 2015 |
| Hybrid Projects Ltd | Financial services | 2021 |
| Hybrid Rentals Ltd | Real estate | 2022 |
| Hybrid Sports Medicine Limited | Health & social care | 2014 |
| Hywel Elias Consulting Limited | Professional & scientific | 2011 |
| I & S Holdings Limited | Financial services | 2008 |
| IAN Walker Accountancy Services Ltd | Professional & scientific | 2006 |
| IAN Walters Property Letting and Management Limited | Real estate | 2013 |
| Idea Maker Limited | Professional & scientific | 2013 |
| Ideacart Technologies Ltd | Education | 2025 |
| Ignite + Inspire Ltd | Education | 2014 |