| Gateway Marketing Ltd | Professional & scientific | 2025 |
| GD Davies Electrical Ltd | Construction | 2026 |
| GEE ENN Properties Limited | Real estate | 2021 |
| Geeneiya Ltd | Wholesale & retail | 2024 |
| Gelli Lower Ltd | Agriculture & fishing | 2025 |
| Gelli Upper Ltd | Agriculture & fishing | 2025 |
| Gelliwastad Holdings Ltd | Real estate | 2015 |
| Genesis Future E-Commerce Co., Ltd | Wholesale & retail | 2026 |
| Genovia Trade Ltd | Wholesale & retail | 2025 |
| Genu Prima Limited | Manufacturing | 2019 |
| George D James Limited | Extraterritorial | 2021 |
| Geospatial Environmental Solutions (GES) Limited | Professional & scientific | 2023 |
| Geraint Havard Jones Limited | Information & communication | 2017 |
| Geraint Morgan Travel Ltd | Administrative & support | 2014 |
| Gethin Williams Ltd | Information & communication | 2017 |
| Getsent Ltd | Wholesale & retail | 2025 |
| Gettasub Limited | Financial services | 2018 |
| GF Plus Ltd | Hospitality | 2019 |
| Ghost Gallery Limited | Arts & recreation | 2020 |
| Giant's Toolbox Ltd | Wholesale & retail | 2026 |
| Gill Waste Recycling Limited | Water & waste | 2008 |
| Ginger Bear Bakery Limited | Hospitality | 2018 |
| Ginger Pizza Company Limited | Hospitality | 2023 |
| GKE Property Management Ltd | Real estate | 2025 |
| Glamorgan Accommodation (III) Limited | Education | 1993 |
| Glamorgan Accountants Limited | Professional & scientific | 2024 |
| Glamorgan Environmental Research Limited | Education | 1993 |
| Glamorgan Online Limited | Education | 2003 |
| Glamorgan Trading Limited | Wholesale & retail | 2024 |
| Glas Business Solutions Limited | Administrative & support | 2010 |
| Gledo Trade UK Ltd | Wholesale & retail | 2025 |
| Glen Hillier Limited | Health & social care | 2018 |
| Glentec Ltd | Construction | 2024 |
| Global Developers Limited | Real estate | 2025 |
| Global White UK Ltd | Wholesale & retail | 2023 |
| Glyncoch Community Regeneration Ltd | Education | 2010 |
| Glyncoch Pharmacy Limited | Wholesale & retail | 2014 |
| Godden Formwork Limited | Wholesale & retail | 1989 |
| Godspeed Brakes Limited | Manufacturing | 2020 |
| Gofal Investments Limited | Financial services | 2024 |
| Goktug Ltd | Transport & logistics | 2023 |
| Goldcliff Holdings Limited | Financial services | 2025 |
| Golden Dragon 109 Limited | Hospitality | 2017 |
| Golden Grace Dinner Limited | Hospitality | 2025 |
| Golden Serandib Ventures Ltd | Hospitality | 2025 |
| Goldtoma Ltd | Wholesale & retail | 2025 |
| Googoo Beauty Limited | Wholesale & retail | 2024 |
| Gorilla Van Conversions Limited | Manufacturing | 2025 |
| Gorilla Vans Ltd | Wholesale & retail | 2021 |
| Gosling Enterprises Limited | Professional & scientific | 2012 |
| GP PM Services Ltd | Professional & scientific | 2023 |
| GPJ Installations Limited | Construction | 2011 |
| GPS Supply Chain UK Ltd | Wholesale & retail | 2025 |
| Gradway Education Limited | Professional & scientific | 2025 |
| Graig Convenience Stores Limited | Wholesale & retail | 2020 |
| Graig Environmental Recycling Services Limited | Manufacturing | 1998 |
| Graig Village Green Ltd | Other services | 2015 |
| Graintuc Properties Ltd | Real estate | 2025 |
| Grandview Technology Ltd | Wholesale & retail | 2025 |
| Granelli Scaffolding Limited | Construction | 2026 |
| Graphite Communications Limited | Professional & scientific | 2019 |
| Gray Stern Investments Limited | Hospitality | 2020 |
| Green Nest Properties Ltd | Real estate | 2024 |
| Greenaway Autos Limited | Wholesale & retail | 2014 |
| Greenfields Energy Consultancy Limited | Professional & scientific | 2016 |
| Greenkids International Limited | Wholesale & retail | 2026 |
| Greenshire Solutions Limited | Construction | 2013 |
| Greensquares Holdings Limited | Financial services | 2025 |
| Greensquares Products Limited | Wholesale & retail | 2004 |
| Greentech M & E Consultants Ltd | Professional & scientific | 2024 |
| Grey Rayne Ltd | Wholesale & retail | 2022 |
| Grey Rayne Property Management Limited | Real estate | 2018 |
| Griffiths Carpentry Ltd | Construction | 2011 |
| Griffiths Security & Smart Technology Ltd | Administrative & support | 2021 |
| Grill & Pizzeria Ltd | Hospitality | 2026 |
| Group Rocket Ltd | Real estate | 2020 |
| Group Rocket Property Ltd | Real estate | 2021 |
| Growing Space Pontypridd C.I.C. | Agriculture & fishing | 2022 |
| Gruff Rees Electrical Ltd | Construction | 2025 |
| GSL Communications Limited | Construction | 2023 |
| GSW Peak Development Ltd | Real estate | 2022 |
| GT Edwards Studios Limited | Information & communication | 2023 |
| GTB Mortgages Ltd | Financial services | 2023 |
| Gtfm (South Wales) Ltd. | Information & communication | 2003 |
| Gtmotorcycle Ltd | Wholesale & retail | 2026 |
| Guardians for Heroes CIC | Administrative & support | 2017 |
| Guerin Properties Limited | Real estate | 2023 |
| Guesttalk Ltd | Information & communication | 2006 |
| Gunes Catering Ltd | Hospitality | 2024 |
| Gurasis Ltd | Transport & logistics | 2025 |
| GW Developments Limited | Construction | 2013 |
| GW1 Limited | Real estate | 2015 |
| Gwaelod-Y-Garth DC Ltd | Health & social care | 2024 |
| Gwalia Healthcare Limited | Manufacturing | 2015 |
| Gwent Investments Limited | Financial services | 2014 |
| Gwgl Carpentry Limited | Construction | 2016 |
| Gwynns Opticians Group Limited | Health & social care | 1977 |
| Gwynt Y Ddraig Cider Ltd | Manufacturing | 2004 |
| H D Williams Ltd | Administrative & support | 2007 |
| H Factor Development CYF | Construction | 2020 |