| GIL Cabs Limited | Transport & logistics | 2025 |
| Gilbertscliffe Properties Limited | Households | 1987 |
| Gileston Manor Properties Limited | Households | 2017 |
| Gilky Tours Ltd | Administrative & support | 2024 |
| Gill Green Psychological Services Ltd | Hospitality | 2017 |
| Gill's Store Ltd | Wholesale & retail | 2014 |
| GIMI99 Ltd | Transport & logistics | 2020 |
| GIN NE Sais Quoi Cardiff Limited | Hospitality | 2020 |
| Ginger Indian Restaurant Ltd | Hospitality | 2019 |
| Ginger Mutts Ltd | Other services | 2022 |
| Ginger Rock Limited | Real estate | 2022 |
| Gioali Ltd | Administrative & support | 2025 |
| Giorgi Ltd | Hospitality | 2012 |
| Giorgio Penlan Ltd | Hospitality | 2025 |
| Gisow Limited | Professional & scientific | 2018 |
| Gissit Ltd | Information & communication | 2008 |
| Giving Works Initiative CIC | Wholesale & retail | 2026 |
| Gizcart Limited | Information & communication | 2014 |
| GJ & LJ Property Ltd | Real estate | 2021 |
| GJ & MR Holding Ltd | Financial services | 2022 |
| GJ Car Clinic Limited | Other services | 2013 |
| Gj-Pic Ltd | Real estate | 2022 |
| GJB Mayhill Limited | Wholesale & retail | 2016 |
| GJL Electrical Services Limited | Manufacturing | 1995 |
| GJN Properties Limited | Financial services | 2024 |
| GJP Homes Ltd | Real estate | 2018 |
| GJT (Bridgend) Ltd | Construction | 2023 |
| GKH Trading Ltd | Wholesale & retail | 2022 |
| Gkshs Limited | Real estate | 2020 |
| GL James Electrical Ltd | Construction | 2023 |
| GL Meats (Pontardawe) Ltd | Wholesale & retail | 2025 |
| Gladeborough Limited | Real estate | 1971 |
| Gladstone Legal Services Ltd | Administrative & support | 2011 |
| Gladys Properties Ltd | Real estate | 2026 |
| Glain Property Services Limited | Construction | 2007 |
| Glais Rugby Football Club Limited | Arts & recreation | 2019 |
| Glamorgan AV Limited | Information & communication | 2005 |
| Glamorgan Commercial Limited | Real estate | 2022 |
| Glamorgan Construction Limited | Construction | 2015 |
| Glamorgan Diagnostic Ltd | Health & social care | 2013 |
| Glamorgan Tailoring Limited | Manufacturing | 2009 |
| Glan Teifi Trusses and Roofing Supplies Ltd | Manufacturing | 2016 |
| Glan Y MOR Aesthetics Limited | Other services | 2024 |
| Glan YR Afon Management Company (NO 3) Limited | Real estate | 1992 |
| Glan YR Afon Management Company (NO 4) Limited | Real estate | 1992 |
| Glanmor Property Developments Two Limited | Real estate | 2023 |
| Glanmor Property Limited | Financial services | 2020 |
| Glanmor Property Management Limited | Real estate | 2021 |
| Glanmorfa Hydrotherapy Centre Ltd | Health & social care | 2016 |
| Glantawe Carpets (1977) Ltd | Wholesale & retail | 2021 |
| Glantawe Carpets Limited | Other services | 2015 |
| Glantawe Investments Limited | Real estate | 1959 |
| Glantawe Landscapes & Tree Services Ltd. | Administrative & support | 2016 |
| Glasfryn Private Nursing and Residential Home Limited | Health & social care | 2000 |
| Glass Tech Windscreens Ltd | Wholesale & retail | 2016 |
| Glasshorizon Designs Ltd | Construction | 2023 |
| Glazbuild Ltd | Wholesale & retail | 2009 |
| GLC Living Limited | Households | 2017 |
| Glen Anthracite Distribution Limited | Mining & quarrying | 1989 |
| Glim Ltd | Real estate | 2023 |
| Global Church Ministries Network Limited | Other services | 2010 |
| Global Educational Matters Ltd | Education | 2015 |
| Global Geomatics Limited | Professional & scientific | 2006 |
| Global Lighting & Vision Systems Ltd | Extraterritorial | 2015 |
| Global Metro Ltd | Wholesale & retail | 2013 |
| Global Netsite Limited | Information & communication | 1997 |
| Global Pet Register Ltd. | Other services | 2009 |
| Global Rail and Construction Solutions Limited | Construction | 2013 |
| Global Self Storage Ltd | Other services | 2019 |
| Globarkart Ltd | Wholesale & retail | 2025 |
| Globe FM Limited | Administrative & support | 2019 |
| Globepleat Limited | Professional & scientific | 2021 |
| Gloucester Place Limited | Hospitality | 2020 |
| Glow & Relax Limited | Wholesale & retail | 2024 |
| Glow Haven Ltd | Other services | 2025 |
| Glow Home Services Limited | Administrative & support | 2016 |
| Glow&Co Ltd | Other services | 2022 |
| Glow-Sol Limited | Other services | 2025 |
| Glrc Ltd | Professional & scientific | 2012 |
| GLS Wales Limited | Manufacturing | 2001 |
| Glynderwen Limited | Construction | 2024 |
| Glyndwr (Tanabi Films) Ltd | Information & communication | 2017 |
| Glyngorse Farm & Leisure Ltd | Agriculture & fishing | 2023 |
| Glynsiriol Limited | Real estate | 2026 |
| Glôw MÔR Skin Ltd | Health & social care | 2025 |
| GM Construction Services Limited | Construction | 2000 |
| GM Hospitality Group Ltd | Hospitality | 2017 |
| GM Landscape Holdings Ltd | Administrative & support | 2025 |
| GMB (South Wales) Limited | Manufacturing | 2014 |
| GME Office Solutions Limited | Manufacturing | 2025 |
| GME Property Management Ltd | Households | 2026 |
| GMZ Enterprise Ltd | Wholesale & retail | 2025 |
| Gnhm Ltd | Hospitality | 2026 |
| GNR Electrical Ltd | Construction | 2020 |
| Go Barista Limited | Hospitality | 2025 |
| Go Explore Campers Limited | Wholesale & retail | 2016 |
| Go FAR Business Coaching Limited | Professional & scientific | 2023 |
| Go Floor Ltd | Construction | 2023 |
| Go Kart Daddy Ltd | Wholesale & retail | 2018 |
| Go Quick Convenience Ltd | Wholesale & retail | 2020 |