| FSB Alpha Limited | Real estate | 2026 |
| FSB Developments Ltd | Real estate | 2026 |
| FSB Park View Limited | Real estate | 2026 |
| FSB Trading Limited | Real estate | 2025 |
| FT Dine Ltd | Extraterritorial | 2019 |
| Fullbrooks Bistro Limited | Hospitality | 2016 |
| Fully Functional Fitness Ltd | Arts & recreation | 2021 |
| Function SFR Ltd | Arts & recreation | 2023 |
| Fungrenade Ltd. | Other services | 2009 |
| Funnel Sketchers Ltd | Administrative & support | 2019 |
| Futur Web Media Ltd | Information & communication | 2024 |
| Future Focus Research Limited | Professional & scientific | 2010 |
| G&B Estates Ltd | Real estate | 2025 |
| G&T Property Development Ltd | Construction | 2025 |
| G.D. Evans Holdings Limited | Construction | 1975 |
| G.D. Evans Investments Limited | Financial services | 1996 |
| Galahad Engineering Services Ltd | Construction | 2020 |
| Galle Finance Limited | Professional & scientific | 2015 |
| Gallu Learning Ltd | Education | 2026 |
| Garmel Property Management Limited | Real estate | 2017 |
| Garth Isaf Equestrian Ltd | Agriculture & fishing | 2019 |
| Garw Pharma Ltd | Wholesale & retail | 2026 |
| GAS Link Industrial Limited | Wholesale & retail | 2015 |
| GAS Link Wales & West Ltd | Wholesale & retail | 2002 |
| Gas-Link Wales Limited | Hospitality | 2003 |
| GEM Motors Limited | Wholesale & retail | 2013 |
| Geodat AI Limited | Professional & scientific | 2025 |
| Gethin R. Ellis Limited | Health & social care | 2016 |
| Gill Rudge Consulting Ltd | Professional & scientific | 2011 |
| Gill's Property Developments Ltd | Real estate | 2026 |
| Gina's Hair Boutique Ltd | Other services | 2024 |
| GL Gold Ltd | Information & communication | 2021 |
| Glam Loft Makeup Ltd | Other services | 2023 |
| Glamorgan Washing Limited | Administrative & support | 2019 |
| Glantaf Biofarma Ltd | Health & social care | 2020 |
| Glass Master U.K Ltd | Construction | 2024 |
| GLP Financial Services Limited | Professional & scientific | 2025 |
| GLS Carpentry Ltd | Construction | 2026 |
| Glân Cleaning Services Limited | Administrative & support | 2015 |
| Golf in Class Limited | Arts & recreation | 2025 |
| Gomusicproductions Ltd | Arts & recreation | 2024 |
| GOODRIDGE15 Ltd | Arts & recreation | 2022 |
| GPE Holdings Ltd | Real estate | 2026 |
| Green Asset Solutions Limited | Construction | 2013 |
| Greenwich Food Ingredients Ltd | Manufacturing | 2025 |
| Grgrl Limited | Financial services | 2025 |
| Griffiths Engineering Services Limited | Professional & scientific | 2024 |
| Griffiths Properties LLP | | 2017 |
| Griffiths Property Rentals Ltd | Real estate | 2021 |
| Grimm Designs Limited | Professional & scientific | 2012 |
| Ground UP Building Contractors Ltd | Construction | 2024 |
| Gs&V Ltd | Wholesale & retail | 2020 |
| GT Superbikes Limited | Wholesale & retail | 2004 |
| GT Vehicle Services Ltd | Wholesale & retail | 2019 |
| GUT Instinct Holdings Limited | Wholesale & retail | 2026 |
| Gwc-Cymru CYF | Professional & scientific | 2025 |
| GWL Aviation Limited | Transport & logistics | 2022 |
| H&H Onthego Limited | Manufacturing | 2024 |
| Hafren Consulting LLP | | 2007 |
| Hafren Contracts Limited | Construction | 2008 |
| Hair by Emily Harriet Ltd | Other services | 2026 |
| Hales Housing Limited | Real estate | 2024 |
| Hanesyn Ltd. | Arts & recreation | 2018 |
| Harding Roofing and Construction Ltd | Construction | 2025 |
| Harlequin Care Ltd | Health & social care | 2022 |
| Harlequinn Limited | Manufacturing | 1997 |
| Harness Intent Ltd | Information & communication | 2026 |
| Harry Steele Ltd | Information & communication | 2019 |
| Harry's Bar and Grill (Cowbridge) Ltd | Administrative & support | 2019 |
| Harvey Environmental Ltd | Professional & scientific | 2023 |
| Haus of Stone Ltd | Administrative & support | 2018 |
| Haveli Banqueting Cardiff Ltd | Hospitality | 2025 |
| Haveli Banqueting Limited | Hospitality | 2022 |
| Haveli Group Ltd | Hospitality | 2025 |
| Haveli Hotel Ltd | Hospitality | 2022 |
| Hayman.Dev Ltd | Information & communication | 2021 |
| HCE Adventure Limited | Hospitality | 1997 |
| HDC Enterprises Limited | Administrative & support | 2017 |
| Heathcote Chiropractic Ltd | Health & social care | 2026 |
| Heights Legal Limited | Professional & scientific | 2010 |
| Hellasfrappe Ltd | Other services | 2018 |
| Hendrewen Holdings Limited | Households | 2018 |
| Hepworth Blinds and Shutters Limited | Wholesale & retail | 2024 |
| Hepworth Blinds Limited | Manufacturing | 2019 |
| Hexia Web Services Limited | Information & communication | 2016 |
| Higgzy Limited | Arts & recreation | 2026 |
| Highadmit Building Services Holdings Ltd | Financial services | 2022 |
| Highadmit Projects Limited | Construction | 1992 |
| Highadmit Projects Mechanical Ltd | Construction | 2022 |
| Highways Group Inc. Ltd | Construction | 2017 |
| HOE Property Developments Limited | Construction | 2005 |
| Hogfather Cafe Limited | Hospitality | 2025 |
| Home Taste 2026 Limited | Hospitality | 2026 |
| Hope & FLO Developments Ltd | Real estate | 2023 |
| Hope Haven (Veterans Support) CIC | Education | 2025 |
| Hope Rescue | Other services | 2009 |
| Horizon Civil Engineering Limited | Construction | 2008 |
| Hospital and Prison Action Network (Hpan) CIC | Health & social care | 2022 |
| Hothouse Plumbing Limited | Construction | 2013 |
| HOUSE19 Ltd | Real estate | 2024 |