| Rebecca Oldfield Jewellery Limited | Manufacturing | 2026 |
| Rebekah Ella Ltd | Wholesale & retail | 2020 |
| Rebekah Zink Media Ltd | Information & communication | 2025 |
| Rebel ADS Ltd | Professional & scientific | 2025 |
| Rebel Alliance Audio Ltd | Arts & recreation | 2016 |
| Rebel Alliance Limited | Wholesale & retail | 2020 |
| Rebel Lion Advertising Limited | Professional & scientific | 2022 |
| Rebel Transport Ltd | Transport & logistics | 2014 |
| Rebellion Sports Ltd | Arts & recreation | 2022 |
| Rebooted Solutions Ltd | Information & communication | 2016 |
| Reborn 4X4 Ltd | Wholesale & retail | 2024 |
| REBORN1 Ltd | Other services | 2025 |
| Rebrann Ltd | Administrative & support | 2026 |
| Rebus Data Services UK Limited | Information & communication | 2020 |
| REC Consult UK Ltd | Professional & scientific | 2023 |
| Recell Tech Cardiff Ltd | Wholesale & retail | 2025 |
| Recep Ltd | Wholesale & retail | 2025 |
| Receptive Ltd | Wholesale & retail | 2020 |
| Recharge Solutions Limited | Manufacturing | 2021 |
| Recite & Rise Limited | Education | 2024 |
| Reclona Ltd | Hospitality | 2017 |
| Recolution Recruitment Group Limited | Administrative & support | 2018 |
| Reconstruct 25 Ltd | Financial services | 2025 |
| Record Films Ltd | Arts & recreation | 2025 |
| Recover My Data Ltd | Information & communication | 2019 |
| Recoverbtc Ltd | Other services | 2022 |
| Recovery Case Management Ltd | Health & social care | 2022 |
| Recovery Cymru Community | Other services | 2013 |
| Recovery Services Ltd | Wholesale & retail | 2017 |
| Recovery Wellness Club Limited | Other services | 2023 |
| Recreate Limited | Construction | 2018 |
| Recruitbase Ltd | Administrative & support | 2023 |
| Recruiterjets Ltd | Administrative & support | 2019 |
| Recruitment AG Ltd | Public administration | 2023 |
| Recruitment Courier Ltd | Transport & logistics | 2019 |
| Recruitment Resources Ltd | Administrative & support | 2014 |
| Recycle Motors Limited | Wholesale & retail | 2012 |
| Red & Black TV Limited | Information & communication | 2008 |
| Red Apple Finance Limited | Financial services | 2018 |
| Red Arrow Recovery Ltd | Transport & logistics | 2023 |
| Red Badge Electrical Limited | Construction | 2006 |
| Red Balloon Day Nursery Limited | Education | 2002 |
| Red Bear Group Limited | Administrative & support | 2019 |
| Red Bench Investments Ltd | Real estate | 2025 |
| Red Brck Ltd | Information & communication | 2020 |
| Red Brick Fusion Fabrics Limited | Wholesale & retail | 2025 |
| Red Brick Media Group Limited | Professional & scientific | 2007 |
| Red CAP Marketing Ltd | Professional & scientific | 2015 |
| Red Cardiff Ltd | Information & communication | 2025 |
| Red Chilli Pizza Ltd | Hospitality | 2019 |
| Red Dog Technology Ltd | Other services | 2019 |
| Red Dragon (Travel) Limited | Administrative & support | 1968 |
| Red Dragon Desserts Limited | Hospitality | 2023 |
| Red Dragon Fungi Ltd | Agriculture & fishing | 2024 |
| Red Dragon Group Ltd | Administrative & support | 2016 |
| Red Dragon Hotels Limited | Real estate | 2023 |
| Red Dragon Padel Ltd | Construction | 2024 |
| Red Dragon TEE Tours Ltd | Hospitality | 2025 |
| Red Dragon Transport Ltd | Transport & logistics | 2015 |
| Red Dress Productions Limited | Information & communication | 2014 |
| Red Enclave Ltd | Wholesale & retail | 2019 |
| Red Fire Management Limited | Manufacturing | 2021 |
| Red Frog Productions Limited | Information & communication | 2011 |
| Red Garage Cardiff Ltd | Wholesale & retail | 2023 |
| Red Healthcare Ltd | Health & social care | 2021 |
| Red Horse Media Ltd | Information & communication | 2010 |
| Red Horse Prestige Ltd | Administrative & support | 2016 |
| Red House (Bath) Limited | Hospitality | 2017 |
| Red House Builders Limited | Construction | 2020 |
| Red Kings Properties Ltd | Administrative & support | 2025 |
| Red Kite Business Services Limited | Administrative & support | 2011 |
| Red Kite Digital Ltd | Professional & scientific | 2014 |
| Red Kite Law LLP | | 2011 |
| Red Kite Trust Corporation Limited | Professional & scientific | 2025 |
| Red Knight Homes Limited | Construction | 2016 |
| Red Light MCR Ltd | Hospitality | 2021 |
| Red Line Coffee Ltd | Wholesale & retail | 2025 |
| Red Lion Intelligence Ltd | Professional & scientific | 2019 |
| Red Lion Removals Limited | Transport & logistics | 2020 |
| Red Mountain Films Ltd | Information & communication | 2024 |
| Red Mushroom Transport Ltd | Transport & logistics | 2022 |
| Red Octo Limited | Wholesale & retail | 2016 |
| Red on the Floor Ltd | Wholesale & retail | 2026 |
| Red Online Group Ltd | Administrative & support | 2017 |
| Red Phoenix Games Limited | Manufacturing | 2021 |
| Red PI Limited | Education | 2024 |
| Red Reclaim (Notts) Ltd | Construction | 2024 |
| Red Recruitment Solutions Limited | Administrative & support | 2003 |
| Red Rhino Holdings Ltd | Real estate | 2017 |
| Red Robin Solutions Ltd | Administrative & support | 2021 |
| Red Rock Haigh Estates Limited | Real estate | 2003 |
| Red Roofing Ltd | Construction | 2015 |
| Red Rose School Cardiff Limited | Education | 2010 |
| Red Sea Traders Ltd | Wholesale & retail | 2024 |
| Red Seam (the Way) Ltd | Information & communication | 2022 |
| Red Seam Limited | Administrative & support | 2019 |
| Red Spinel Limited | Wholesale & retail | 2025 |
| Red Stairs Ltd | Professional & scientific | 2018 |
| Red Storm Fashion Agency Limited | Wholesale & retail | 2015 |
| Red Sun Express Limited | Professional & scientific | 2006 |