| GAS 4 Wales Limited | Energy | 2013 |
| Gatehouse ICS Ltd | Real estate | 2019 |
| Gelson Refinish UK Ltd. | Wholesale & retail | 2021 |
| GEM Publications Limited | Information & communication | 2025 |
| Gemma Wilson Ltd. | Administrative & support | 2003 |
| Genco Enterprises Limited | Construction | 2003 |
| George Brothers Limited | Construction | 2003 |
| Geraint Williams Limited | Construction | 2002 |
| Gilbern Sports Cars (Components) Limited | Manufacturing | 2016 |
| Gjsl Properties Ltd | Real estate | 2017 |
| GK Accounting Services Ltd | Professional & scientific | 2025 |
| GK Enterprise Food UK Ltd | Hospitality | 2025 |
| Gladiator Adhesive Products Ltd | Wholesale & retail | 2014 |
| Glampawgan Pet Services Ltd | Professional & scientific | 2019 |
| Glenbrae (MH) Limited | Wholesale & retail | 2021 |
| Gleneric Ltd | Health & social care | 2011 |
| Gljones Ltd | Hospitality | 2023 |
| Global Securities Limited | Real estate | 1962 |
| Globalinks Group Limited | Professional & scientific | 2023 |
| Golchdu Tybie Limited | Other services | 2024 |
| Goldbat Consulting Limited | Professional & scientific | 2026 |
| Goose and Cuckoo Holdings Limited | Hospitality | 2007 |
| Goose and Cuckoo Limited | Hospitality | 2005 |
| Gorswen Limited | Transport & logistics | 2014 |
| Gourmet Food (South Wales) Ltd | Hospitality | 2013 |
| Gravelle Family Limited | Administrative & support | 2011 |
| Graymay Limited | Wholesale & retail | 1994 |
| Greater Global AC Ltd | Information & communication | 2022 |
| Green Cocoon Ltd | Professional & scientific | 2025 |
| Green Dragon Rail Solutions Ltd | Administrative & support | 2008 |
| Green Leaf Remediation Ltd | Administrative & support | 2019 |
| Greg Griffiths CYF | Financial services | 2025 |
| Grenig Homes Ltd | Construction | 2023 |
| Grenig Insights Ltd. | Professional & scientific | 2018 |
| Grey Jones Property Ltd | Real estate | 2026 |
| Griffiths Bwtrimawr Memorials Limited | Other services | 2021 |
| Gripstar Limited | Wholesale & retail | 2015 |
| Growing Gwendraeth CIC | Agriculture & fishing | 2020 |
| GRP Consultancy Ltd | Other services | 2025 |
| GRP Development Limited | Manufacturing | 2017 |
| GS Analytical Services Ltd | Extraterritorial | 2024 |
| GW & L Property Limited | Real estate | 2020 |
| Gwenlais Developments Limited | Construction | 2005 |
| Gwyddfan CYF | Education | 2023 |
| Gyda Official Ltd | Hospitality | 2026 |
| H & FW Ltd | Hospitality | 2016 |
| H G Evans Limited | Wholesale & retail | 2001 |
| H L Roberts Limited | Professional & scientific | 2020 |
| Hacer Crown Limited | Construction | 2026 |
| Hafan Catering Ltd | Hospitality | 2022 |
| Harckle Ltd | Real estate | 2025 |
| Hathaway Training Limited | Transport & logistics | 2020 |
| Haul Hyfryd Ltd | Other services | 2023 |
| Haul Y Gwrhyd CIC | Energy | 2025 |
| Hawkar Barber Ltd | Other services | 2024 |
| Haydale Composite Solutions Limited | Professional & scientific | 1992 |
| Haydale Graphene Industries Limited | Extraterritorial | 2015 |
| Haydale PLC | Professional & scientific | 2010 |
| Haydale Technologies Limited | Manufacturing | 2003 |
| Headfirst Training Limited | Education | 2023 |
| Headhunterz Limited | Administrative & support | 2025 |
| Heath Capital Ltd | Financial services | 2026 |
| Heath Commercial Properties Ltd | Real estate | 2026 |
| Hendre Holdings Limited | Professional & scientific | 1998 |
| Hendre Homes Limited | Construction | 2001 |
| Heol 1962 Limited | Extraterritorial | 2014 |
| Hewsan Limited | Professional & scientific | 1988 |
| Hi-Lex ACT Wales Ltd | Manufacturing | 1999 |
| HMY CC Limited | Wholesale & retail | 2022 |
| Hobart Engineering Ltd | Professional & scientific | 2011 |
| Holbar Ltd | Health & social care | 2025 |
| Hollycott Professional Services Ltd | Professional & scientific | 2025 |
| Homehearted Developments Ltd | Construction | 2024 |
| Homehearted Ltd | Financial services | 2020 |
| Homestead Secure Ltd | Financial services | 2025 |
| Hoof Prints 4 Life CIC | Education | 2026 |
| Hope Valley Ammanford CIC | Hospitality | 2025 |
| Hourglass (Wales) Limited | Manufacturing | 2002 |
| HP Production Limited | Information & communication | 2013 |
| HT Capital Investments Ltd | Real estate | 2026 |
| Hudson & Cooper Limited | Other services | 2018 |
| Hughes Decorators Limited | Construction | 2002 |
| Hundredandtenpercent Ltd | Wholesale & retail | 2025 |
| Hunkz & Honeyz Ltd | Other services | 2022 |
| Husky Protection Limited | Financial services | 2023 |
| Hutson Holdings Limited | Financial services | 2023 |
| HUW Morgan Carpentry Limited | Construction | 2018 |
| HW Reform Ltd | Administrative & support | 2012 |
| Hyfryd Estate Management Ltd | Real estate | 2023 |
| Hyfryd Ltd | Construction | 2026 |
| I C Vapes Ltd | Wholesale & retail | 2024 |
| I M Cooper Services Ltd | Professional & scientific | 2021 |
| I Planning Wealth Management Ltd | Financial services | 2010 |
| I. Flex Repair Ltd | Wholesale & retail | 2025 |
| Ignite(Training Wales) Ltd | Education | 2024 |
| Illuminate Electrical Services Ltd | Construction | 2019 |
| Impact Fire Protection Ltd | Construction | 2025 |
| IN2ACTION - Cymru | Other services | 2009 |
| Indiemax Ltd | Arts & recreation | 2021 |
| Indifference Proud to BE C.I.C. | Health & social care | 2015 |