| Radrow Holdings Limited | Construction | 2016 |
| Rads Cars Ltd | Extraterritorial | 2015 |
| Raglan Consulting Limited | Information & communication | 2021 |
| RAI Houses Limited | Real estate | 2024 |
| Rail Decarbonisation Research Group Limited | Professional & scientific | 2021 |
| Railway Summer Camp CIC | Education | 2026 |
| RAJ Solutions Limited | Information & communication | 2015 |
| Raja Consulting Ltd | Information & communication | 2018 |
| RAK Physio & Sports Clinic Ltd | Health & social care | 2023 |
| Rakker Consulting Limited | Professional & scientific | 2023 |
| Rambra (UK) Limited | Wholesale & retail | 2003 |
| Ramnit Holdings Ltd | Financial services | 2026 |
| Ranidae LLP | | 2008 |
| Ranjan Services Limited | Health & social care | 2016 |
| Rank (U.K.) Holdings Limited | Professional & scientific | 1992 |
| Rank Casino Holdings Limited | Professional & scientific | 2011 |
| Rank Digital Holdings Limited | Professional & scientific | 2017 |
| Rank Digital Limited | Arts & recreation | 1999 |
| Rank Group Finance PLC | Financial services | 1985 |
| Rank Group Gaming Division Limited | Professional & scientific | 1996 |
| Rank Group Holdings Limited | Financial services | 1976 |
| Rank Interactive Limited | Arts & recreation | 2017 |
| Rank Leisure Holdings Limited | Professional & scientific | 1984 |
| Rank Leisure Limited | Arts & recreation | 1997 |
| Rank Leisure Machine Services Limited | Arts & recreation | 1960 |
| Rank Nemo (Twenty-Five) Limited | Professional & scientific | 2002 |
| Rank Overseas Holdings Limited | Professional & scientific | 1946 |
| Rank Speciality Catering Limited | Extraterritorial | 1948 |
| Rapidd Design & Build Ltd | Construction | 2014 |
| Ravas UK Limited | Administrative & support | 2007 |
| Rawfluence Ltd | Wholesale & retail | 2025 |
| Rawstock London Limited | Professional & scientific | 2007 |
| RAX AV Limited | Administrative & support | 2012 |
| RAY AAA Limited | Real estate | 2017 |
| RAY Drive Management Company Limited | Professional & scientific | 1987 |
| RAY ESS Consulting Ltd | Professional & scientific | 2023 |
| RAY of Hearing Ltd | Wholesale & retail | 2026 |
| Rayfield Ltd | Information & communication | 2019 |
| Rayfield Management (Maidenhead) Ltd | Households | 2014 |
| Raymill Consultancy Ltd | Professional & scientific | 2025 |
| Raymond Proclean Limited | Administrative & support | 2024 |
| Raziq Kareem Ltd | Wholesale & retail | 2025 |
| RB Treemasters Ltd | Agriculture & fishing | 2008 |
| RBS Construction Services Limited | Construction | 2014 |
| Rbwm Limited | Real estate | 2025 |
| RCG Brickwork Limited | Construction | 2018 |
| RCS PM Consulting Ltd | Information & communication | 2020 |
| RD Pharma Consulting Ltd | Professional & scientific | 2024 |
| RDD Media Productions Ltd | Information & communication | 2026 |
| RDH Legal Limited | Other services | 2025 |
| RE & I Limited | Professional & scientific | 2023 |
| Reach Solutions Europe Ltd | Wholesale & retail | 2025 |
| REACH-4-IT Limited | Professional & scientific | 2000 |
| Real Construction Work Ltd | Construction | 2020 |
| Real Estate Bonding Limited | Financial services | 2014 |
| Realizer Ltd | Information & communication | 2023 |
| Really Something Ltd | Education | 2023 |
| Realm Info Tech Limited | Information & communication | 2019 |
| Realworld Advertising Limited | Administrative & support | 2015 |
| Ream Capital Partners Limited | Administrative & support | 2010 |
| Rebecca Barnett Growth Marketing Ltd | Professional & scientific | 2026 |
| Rebecca Mcclelland Limited | Arts & recreation | 2022 |
| Rebecca Walton Consulting Ltd | Professional & scientific | 2020 |
| Rebel Rental Limited | Real estate | 2018 |
| Rebels and Pilgrims Collective CIC | Education | 2025 |
| Rebels and Pilgrims Ltd | Arts & recreation | 2022 |
| Rebo UK Limited | Wholesale & retail | 2006 |
| Recenso Consulting Limited | Information & communication | 2017 |
| Recordati Rare Diseases UK Limited | Wholesale & retail | 1996 |
| Recruit Zone Limited | Administrative & support | 2012 |
| Recruitment Revolution.Com Limited | Administrative & support | 2005 |
| Red and Black Healthcare Limited | Health & social care | 2012 |
| Red Cube IT Ltd | Information & communication | 2010 |
| Red Door Productions Ltd | Information & communication | 2013 |
| Red HAT Solutions Ltd | Professional & scientific | 2022 |
| Red Kite Advice and Consulting Ltd | Professional & scientific | 2011 |
| Red Laser Limited | Professional & scientific | 2025 |
| Red Nine Consulting Ltd | Information & communication | 2013 |
| Red River Sport Limited | Administrative & support | 2015 |
| Red Wall Designs Ltd | Manufacturing | 2016 |
| Redcot Construction Services Limited | Professional & scientific | 2025 |
| Redfrog.Com Limited | Information & communication | 2006 |
| Redhouse Research Limited | Professional & scientific | 2025 |
| Redmill Properties Limited | Administrative & support | 1999 |
| Redroofs Holdings 2014 Ltd | Financial services | 2014 |
| Redroofs School for the Performing Arts Limited | Arts & recreation | 2014 |
| Redroofs Theatre School Ltd | Arts & recreation | 2013 |
| Redshow Limited | Professional & scientific | 1997 |
| Reed & Rackstraw Limited | Manufacturing | 1995 |
| Reedus Ltd | Information & communication | 2023 |
| Reef Consulting Limited | Professional & scientific | 2023 |
| Reflections Cleaning Services Limited | Administrative & support | 2011 |
| Regain Reform Redefine Ltd | Professional & scientific | 2023 |
| Regal Court Bray Ltd | Real estate | 2011 |
| Regatta Solutions Ltd | Information & communication | 2005 |
| Regency Construction (Maidenhead) Limited | Construction | 2002 |
| Regumind Systems Ltd | Information & communication | 2026 |
| Rehman Consulting Ltd | Information & communication | 2026 |
| Reid Davis Consultancy Ltd | Professional & scientific | 2020 |
| Rejuvapen UK Ltd | Wholesale & retail | 2014 |