| Red Sword Agency Ltd | Other services | 2020 |
| Red Watch Fire & Security Ltd | Administrative & support | 2026 |
| Red Wire Media Ltd | Information & communication | 2010 |
| Red Wolf Global Recruitment Ltd | Information & communication | 2019 |
| Red Wolf Marketing Limited | Information & communication | 2014 |
| Red-Cuffe Ltd | Construction | 2019 |
| RED4D TM Ltd | Construction | 2019 |
| RED5 Electrical Limited | Construction | 2025 |
| RED5 Renovations Limited | Real estate | 2021 |
| Redamoh Security Services Limited | Administrative & support | 2015 |
| Redb Services Limited | Administrative & support | 2019 |
| Redbrick Heating & Plumbing Ltd | Construction | 2024 |
| REDBUSE1 Ltd | Administrative & support | 2023 |
| Redco Process Engineering Company Ltd | Water & waste | 2025 |
| Redcortex Ltd | Information & communication | 2016 |
| Redcow Distributions Limited | Wholesale & retail | 2018 |
| Reddy Groups Ltd | Wholesale & retail | 2022 |
| Reddy PAI Metals Ltd | Wholesale & retail | 2011 |
| Reddy's Tech Ltd | Professional & scientific | 2017 |
| Redeemltc Ltd | Wholesale & retail | 2024 |
| Redefined by VIP Limited | Professional & scientific | 2022 |
| Redek Consulting Ltd | Information & communication | 2023 |
| Redericbea Limited | Manufacturing | 2023 |
| Redfern and Sheraton Coaching and Mentoring Ltd | Other services | 2025 |
| Redfern Worldwide Trading Ltd | Wholesale & retail | 2025 |
| Redfish Holdings Limited | Financial services | 2025 |
| Redfish Promotions Limited | Manufacturing | 2025 |
| Redford Property Ltd | Real estate | 2019 |
| Redgenesis Ltd | Wholesale & retail | 2026 |
| Redhill Bearings (SE) Limited | Wholesale & retail | 2023 |
| Redhill Construction and Developments Ltd | Manufacturing | 2018 |
| Redhill Engineering Ltd | Professional & scientific | 2023 |
| Redi 207 Limited | Real estate | 2011 |
| Redi 210 Limited | Real estate | 2013 |
| Redi 211 Limited | Real estate | 2013 |
| Redi 212 Limited | Real estate | 2014 |
| Redi 213 Limited | Real estate | 2014 |
| Redi 214 Limited | Real estate | 2015 |
| REDI-94 Limited | Real estate | 2002 |
| Redi-Ahead Limited | Professional & scientific | 2005 |
| Redinex Solutions Limited | Construction | 2018 |
| Redknight Consultancy Ltd | Administrative & support | 2014 |
| Redline Facilities Limited | Construction | 2014 |
| Redline International Limited | Transport & logistics | 2017 |
| Redline Racing Motorsport Ltd Trading AS Redline Ltd | Wholesale & retail | 2009 |
| Redlion-Hoj Ltd | Hospitality | 2017 |
| Redman Contracting Limited | Construction | 2019 |
| Redmayne Brackley Limited | Wholesale & retail | 2024 |
| Redmore Recruitment Limited | Administrative & support | 2023 |
| Redospace Ltd | Wholesale & retail | 2022 |
| Redoubt Investments Limited | Real estate | 2022 |
| Redprr Ltd | Other services | 2025 |
| Redrose Kitchen Ltd | Hospitality | 2018 |
| Reds Development Services Limited | Professional & scientific | 2006 |
| Redsky Leadership Development Limited | Professional & scientific | 2025 |
| Redston Properties Ltd | Real estate | 2026 |
| Redstone Consultancy Ltd | Professional & scientific | 2024 |
| Redstoneuk Limited | Real estate | 2020 |
| Redtag Technology Ltd | Information & communication | 2013 |
| Redtechengineering Limited | Professional & scientific | 2024 |
| Redway Removals Ltd | Transport & logistics | 2025 |
| Redwood (Wales) Limited | Construction | 2012 |
| Redwood Associates Limited | Other services | 2018 |
| Redwood Construction Cardiff Limited | Construction | 2014 |
| Redwood Court (Llanishen) Limited | Real estate | 1992 |
| Redwood Properties Cardiff Limited | Real estate | 2021 |
| Redy Services Limited | Professional & scientific | 2025 |
| Reecii Designs Limited | Construction | 2019 |
| Reed Wolf Ltd | Professional & scientific | 2018 |
| Reeds Insurance Brokers Limited | Financial services | 2002 |
| Reeds Leasing Limited | Administrative & support | 2002 |
| Reeds Lifestyle Ltd | Wholesale & retail | 2024 |
| Reeds Rayner Limited | Extraterritorial | 2026 |
| Reef Lounge Aquatics Ltd | Wholesale & retail | 2018 |
| Reehan Ltd | Wholesale & retail | 2025 |
| Reel Stories of Hope Limited | Arts & recreation | 2025 |
| Reend Trading Limited | Manufacturing | 2025 |
| Rees & Kirby Limited | | 1900 |
| Rees & Moore Limited | Real estate | 1998 |
| Rees Enterprises Limited | Households | 2018 |
| Rees Group Construction Ltd | Construction | 2018 |
| Rees Hough (Civil Engineering) Limited | Wholesale & retail | 1981 |
| Rees Property Group Ltd | Real estate | 2022 |
| Rees Rail and Construction Ltd | Professional & scientific | 2010 |
| Rees Reynolds Partnership Limited | Other services | 2021 |
| Rees Wood Terry Limited | Professional & scientific | 2003 |
| Reeses Limited | Construction | 2024 |
| Reeses Sweeps Ltd | Administrative & support | 2024 |
| Reeves Disability Consultancy CIC | Health & social care | 2025 |
| REF Contracts Ltd | Construction | 2019 |
| Refass Constructions and Investments Ltd | Construction | 2018 |
| Refends Cleaning Services Ltd | Other services | 2023 |
| Refine Gifts Customized Limited | Wholesale & retail | 2024 |
| Refinish Supplies UK Ltd | Wholesale & retail | 2022 |
| Refit Interiors Limited | Construction | 2015 |
| Reflection Living Ltd | Real estate | 2020 |
| Reflex Marketing (UK) LLP | | 2012 |
| Reflex Sphere Studios Ltd | Information & communication | 2025 |
| Reflexive Trade Ltd | Wholesale & retail | 2019 |
| Reforce Portal Ltd | Extraterritorial | 2022 |