| Green 4 Wales Limited | Manufacturing | 2019 |
| Green Acre Dairy Limited | Agriculture & fishing | 2024 |
| Green Blockchain Ltd | Financial services | 2021 |
| Green COG Limited | Manufacturing | 2021 |
| Green Grove Farms Ltd | Agriculture & fishing | 2002 |
| Green Pioneering Ltd | Construction | 2017 |
| Greenacre Environmental Services Limited | Administrative & support | 2008 |
| Greener Media Ltd | Information & communication | 2015 |
| Greensleeves Investments Ltd | Financial services | 2024 |
| Greensleeves Property Ltd | Real estate | 2024 |
| Greves Works Ltd | Professional & scientific | 2022 |
| Griffin Castle Limited | Wholesale & retail | 2023 |
| Griffin Selection Ltd | Administrative & support | 2012 |
| Grifftar Ltd | Construction | 2020 |
| Grifftar Signals Ltd | Administrative & support | 2020 |
| Grist Square 1 Ltd. | Hospitality | 2023 |
| Grosvenor Technical Solutions Limited | Information & communication | 2021 |
| Ground Concept Limited | Construction | 2016 |
| Ground Tech Limited | Administrative & support | 2012 |
| Grubs UP Carmarthen Limited | Hospitality | 2024 |
| GS Wellbeing Services Ltd | Health & social care | 2019 |
| GSL Financial Consultants Limited | Financial services | 2007 |
| GT & SON Services Ltd | Construction | 2023 |
| Guardwatch Security ( UK ) Limited | Administrative & support | 2009 |
| Gundi 2024 Ltd | Hospitality | 2024 |
| Guv's Taxis Ltd | Transport & logistics | 2015 |
| GV Surveying Ltd | Professional & scientific | 2024 |
| Gwarffynnon CYF | Wholesale & retail | 2020 |
| Gwasg Gregynog Limited | Information & communication | 1978 |
| Gwawr Newydd Ltd | Real estate | 2013 |
| Gwendraeth Valley Recycling Limited | Water & waste | 2009 |
| Gwenyn Gruffydd Ltd | Agriculture & fishing | 2019 |
| Gwestfa Limited | Real estate | 2010 |
| Gwili Developments Limited | Construction | 2007 |
| Gwili Railway Company Limited | Other services | 1975 |
| Gwili Tyres Ltd | Wholesale & retail | 2024 |
| GWS Developments Ltd | Construction | 2022 |
| Gwyn Lewis Building Services Limited | Construction | 2010 |
| Gwynfan Management Company Limited | Households | 2000 |
| Gwynt Gelli Ltd | Agriculture & fishing | 2012 |
| Gydai’N Gilydd Psychology Assessments Ltd | Education | 2024 |
| Gŵyl Hanes Cymru I Blant / Children's Festival of Welsh History CYF | Arts & recreation | 2015 |
| H & J Howells Limited | Manufacturing | 2011 |
| H B Enoch & Owen Ltd | Professional & scientific | 2013 |
| H C Jones Ltd | Professional & scientific | 2019 |
| H D Capital Investment Ltd | Real estate | 2022 |
| H D Evans & SON Limited | Transport & logistics | 2018 |
| H D Pritchard Probate Limited | Professional & scientific | 2019 |
| H G Griffiths Limited | Transport & logistics | 2008 |
| H Jenkins & Co Ltd | Professional & scientific | 2012 |
| H Security Consultancy Services Limited | Administrative & support | 2025 |
| H.D. Pritchard Limited | Professional & scientific | 2012 |
| H.G.Bryer & Sons Limited | Real estate | 1962 |
| H2N2 CYF | Real estate | 2024 |
| H72 Ltd | Professional & scientific | 2024 |
| Habco (Wales) Limited | Real estate | 1997 |
| Hadio Cwmni Buddiant Cymunedol | Professional & scientific | 2025 |
| Hafan Pererinion CYF | Hospitality | 2021 |
| Hafodneddyn Feeds Ltd | Agriculture & fishing | 2021 |
| Hair by Ashley Edwards Limited | Professional & scientific | 2025 |
| Halen-Mor Ltd | Real estate | 2021 |
| Handford Commercial Repairs Limited | Wholesale & retail | 2023 |
| Handy Hosts Limited | Information & communication | 1999 |
| Hanfords Property Group Limited | Real estate | 2026 |
| Hanley Heritage Investments Ltd | Real estate | 2025 |
| Hanzarlay Ltd | Wholesale & retail | 2023 |
| Harad Electrical Ltd | Construction | 2021 |
| Harcourt Homes Ltd | Real estate | 2024 |
| Hargreaves Engineering (Carms) Limited | Wholesale & retail | 2014 |
| Harris Ecology Ltd | Professional & scientific | 2019 |
| Havard Estates Limited | Construction | 2013 |
| Havard Tisdale Limited | Real estate | 2008 |
| Hawkes Prospective Trading Ltd | Professional & scientific | 2019 |
| HCJ Fit Ltd | Administrative & support | 2024 |
| HCM Enterprises Limited | Professional & scientific | 2011 |
| HCW Optometry Ltd | Health & social care | 2017 |
| HDG Farm Supplies Ltd | Wholesale & retail | 2002 |
| Head for the Hills Glamping Ltd | Hospitality | 2024 |
| Heard Holdings Ltd | Real estate | 2022 |
| Hearing AID Solutions Limited | Health & social care | 2006 |
| Heatwise GAS and Plumbing Services Limited | Construction | 2021 |
| Hefin Thomas Fabrications CYF | Manufacturing | 2024 |
| Hefin Thomas Plant and TAR Limited | Administrative & support | 2008 |
| Heledd Ebsworth Financial Services Limited | Financial services | 2017 |
| Hema Building & Decoration Ltd | Construction | 2014 |
| Hendre Heating Limited | Construction | 2024 |
| Hendy Farms Limited | Agriculture & fishing | 2002 |
| Heol YR Ysgol SVP Ltd | Construction | 2024 |
| Herbert (Pembs) Limited | Real estate | 2023 |
| Herbys Gifts Limited | Wholesale & retail | 2011 |
| Here to There Transport Ltd | Transport & logistics | 2022 |
| Hereford Property Services Limited | Construction | 2020 |
| Heritage Home Essentials Ltd | Manufacturing | 2024 |
| Hestus Ltd | Other services | 2021 |
| HH Plumbing Services Limited | Construction | 2014 |
| High Noon Garage Services Limited | Administrative & support | 1994 |
| Highfieldstreetfood Ltd | Hospitality | 2021 |
| Highly Limited | Professional & scientific | 2018 |
| Hillas Holdings Limited | Real estate | 2024 |
| Hillside Huts Ltd | Hospitality | 2026 |