| Gareth Davies Interiors Ltd | Professional & scientific | 2026 |
| Gareth Davies Project Services Ltd | Professional & scientific | 2016 |
| Gareth L. Edwards Ltd | Real estate | 2008 |
| Gareths Car Valeting Ltd | Administrative & support | 2022 |
| Garfield Stores Ltd | Wholesale & retail | 2023 |
| Garry Lake Ltd | Arts & recreation | 2023 |
| Garw Ltd | Wholesale & retail | 2014 |
| Garw Valley Community Gardens Ltd | Arts & recreation | 2022 |
| Garw Valley Youth Clubs Ltd | Education | 2024 |
| GAS Exploration Finance Limited | Mining & quarrying | 2012 |
| GAS N Gears Limited | Professional & scientific | 2016 |
| GAS Turbine Aviation Ltd | Wholesale & retail | 2023 |
| Gateover Limited | Extraterritorial | 2024 |
| Gatestar Limited | Extraterritorial | 2025 |
| Gava Consultant Limited | Health & social care | 2020 |
| GC Inns & Taverns Limited | Hospitality | 2024 |
| Gclem Holdings Ltd | Financial services | 2021 |
| GDJ Engineering Services Limited | Construction | 2023 |
| GE Pearce Holdings Limited | Financial services | 2024 |
| Geco Services Ltd | Construction | 2025 |
| Geefitness Ltd | Arts & recreation | 2026 |
| Geena Ltd | Extraterritorial | 2019 |
| Geleta Doors Limited | Manufacturing | 2019 |
| Gemini Digital Colour Limited | Manufacturing | 1995 |
| Genesis Auto Services Limited | Wholesale & retail | 2023 |
| Genexsquad Ltd | Information & communication | 2023 |
| Geoff Evans and Sons Haulage Limited | Transport & logistics | 2014 |
| Georgia-Lee Holdings Ltd | Financial services | 2024 |
| Georgie Jones Style Solutions Ltd | Wholesale & retail | 2025 |
| Geospatial Wales Limited | Professional & scientific | 2013 |
| Gerry Evans Consulting Ltd | Professional & scientific | 2009 |
| Getsweaty Limited | Information & communication | 2025 |
| GH Jones Welding Services Ltd | Manufacturing | 2020 |
| GH2 Energy Group Ltd | Manufacturing | 2023 |
| GH2 Energy Ltd | Manufacturing | 2021 |
| GH2 Engineering Ltd | Manufacturing | 2023 |
| GH2 Fuels Ltd | Manufacturing | 2022 |
| GH2 GAS Ltd | Manufacturing | 2022 |
| GH2 Group Ltd | Manufacturing | 2021 |
| GH2 Marine Ltd | Manufacturing | 2021 |
| GH2UK Ltd | Manufacturing | 2023 |
| Ghuman PVT. Limited | Transport & logistics | 2026 |
| Gibson Energy Services Limited | Construction | 2025 |
| Gibson Specialist Technical Services Limited | Energy | 2008 |
| Gibson STS Holdings Limited | Financial services | 2024 |
| Gilds Industrial Solutions Ltd | Manufacturing | 2022 |
| Gilesey Tyre Automotives Ltd | Wholesale & retail | 2021 |
| Gillard Associates Limited | Professional & scientific | 2012 |
| GIO2ANA Limited | Health & social care | 2023 |
| GJ Locks Ltd | Manufacturing | 2014 |
| GJR & SON Construction Limited | Construction | 2022 |
| Gkgpml Ltd | Administrative & support | 2025 |
| Gladeview Limited | Real estate | 1974 |
| Glam Vale Tyre Specialists Limited | Professional & scientific | 1971 |
| Glamorgan 1:1 Financial Limited | Financial services | 2010 |
| Glamorgan Fabrication Ltd | Manufacturing | 1974 |
| Glamorgan Farm Supplies Limited | Agriculture & fishing | 2005 |
| Glamorgan Upholstery Limited | Water & waste | 1992 |
| Glamorganshire Ltd | Information & communication | 2007 |
| Glassic Windows and Doors Ltd | Construction | 2024 |
| Glazing@Metal Fabrication Ltd | Manufacturing | 2023 |
| Gleh Limited | Professional & scientific | 2012 |
| Glenally Chandlers Ltd | Manufacturing | 2023 |
| Glenbrook House Management Limited | Real estate | 2000 |
| Glenride Limited | Extraterritorial | 2017 |
| Glitter Body Art Limited | Wholesale & retail | 2009 |
| GLO I Natur CIC | Professional & scientific | 2025 |
| Glo&Co Ltd | Information & communication | 2022 |
| Glo-Networks Employee Ownership Trustee Ltd | Professional & scientific | 2022 |
| Glo-Networks Limited | Information & communication | 2007 |
| Global Maritime Engineering Services Limited | Professional & scientific | 2016 |
| GLOBAL1PARTNERS Ltd | Wholesale & retail | 1994 |
| GLOBAL1PARTNERS United Kingdom Ltd | Wholesale & retail | 2020 |
| Glowcharge Limited | Real estate | 1986 |
| Glynogwr Properties Limited | Real estate | 2018 |
| Glyntawel Luxury Dog Boarding & Pet Hotel Limited | Hospitality | 2016 |
| GME Holdings Limited | Financial services | 2018 |
| GME Services Limited | Professional & scientific | 2024 |
| Gmec Fleetserve Limited | Wholesale & retail | 2025 |
| Gmec Holdings Limited | Financial services | 2023 |
| Go & Glow Aesthetics Ltd | Other services | 2025 |
| Go EV Cymru C.I.C. | Professional & scientific | 2022 |
| Go Fetch Ltd | Transport & logistics | 2011 |
| Go Green Services Ltd | Construction | 2015 |
| Go Group Ltd | Wholesale & retail | 2021 |
| Go Smart Electrical Ltd | Construction | 2022 |
| Gold Lord Limited | Other services | 2022 |
| Goldbarn Limited | Extraterritorial | 2025 |
| Goldcade Limited | Extraterritorial | 2022 |
| Golden 80 Limited | Hospitality | 2019 |
| Golden Acre Pubs Ltd | Hospitality | 2026 |
| Golden Foods Supply Ltd | Wholesale & retail | 2022 |
| Golden Valley Blaengarw Limited | Hospitality | 2005 |
| Goldrock Limited | Extraterritorial | 2026 |
| Goldwynn Limited | Extraterritorial | 2024 |
| Golf Services Wales Limited | Administrative & support | 2003 |
| Golocal Places Ltd | Information & communication | 2026 |
| Good 2 ORG CIC | Health & social care | 2025 |
| Goodness Grocers Juice Bar Ltd | Hospitality | 2024 |
| Goodone Logistic Limited | Transport & logistics | 2021 |