| Red EYE International Limited | Information & communication | 2000 |
| Red Kiwi Freehold Limited | Real estate | 2019 |
| Red Kiwi Lettings Ltd | Real estate | 2017 |
| Red Lodge Consulting Ltd. | Information & communication | 2011 |
| Red Reign Limited | Professional & scientific | 2013 |
| Red Robot Limited | Professional & scientific | 2010 |
| Red Rock (UK) Ltd | Wholesale & retail | 2013 |
| Red Squirrel Post Limited | Information & communication | 2013 |
| Red Squirrel Wine Ltd. | Wholesale & retail | 2012 |
| Red White & Green Limited | Information & communication | 2001 |
| Red Wolf Coaching Ltd | Professional & scientific | 2022 |
| Red Zebra Media Limited | | 2009 |
| RED2BLUE Limited | Professional & scientific | 2007 |
| Redber Limited | Wholesale & retail | 2010 |
| Redbuzzard Limited | Administrative & support | 2006 |
| Redefine Clinic Ltd | Health & social care | 2018 |
| Redex Solutions Ltd | Real estate | 2021 |
| Redfields Management Company Limited | Real estate | 1985 |
| Redford Education International Ltd | Education | 2013 |
| Redford Global Ltd | Professional & scientific | 2023 |
| Redifon Limited | Information & communication | 2000 |
| Redset Security Limited | Administrative & support | 2021 |
| Redset Solutions Group LLP | | 2021 |
| Redset Solutions Limited | Construction | 2020 |
| Redway Construct Limited | Construction | 2018 |
| Redwingit Services Limited | Professional & scientific | 2009 |
| Redwood Tree Services Limited | Agriculture & fishing | 2004 |
| Redwood Tree Surgeons Ltd | Agriculture & fishing | 2008 |
| Reef Trading | Professional & scientific | 2012 |
| Reekie Properties Limited | Real estate | 2005 |
| Reel Good Training Limited | Information & communication | 2013 |
| Reelvision Media Ltd | Information & communication | 2025 |
| Rees-Stoner Associates Ltd | Professional & scientific | 2012 |
| Reeve Young Consulting Limited | Professional & scientific | 2013 |
| Reeves Lease Limited | Real estate | 2015 |
| Reeves, Spencer & Co Limited | Professional & scientific | 2022 |
| Refinery Media Ltd | Information & communication | 2024 |
| Reflections Flat Management Company Ltd | Households | 2026 |
| Reform Pilates Ltd | Arts & recreation | 2019 |
| Refresh QEP Limited | Hospitality | 2023 |
| Regarde Ltd | Other services | 2023 |
| Regency Lettings & Property Management Limited | Real estate | 2011 |
| Regency Transport Solutions Limited | Transport & logistics | 2009 |
| REGENER8 Fairthorne Limited | Energy | 2024 |
| REGENER8 Group Limited | Financial services | 2022 |
| REGENER8 NZ Management Ltd | Energy | 2023 |
| REGENER8 Power Limited | Other services | 2018 |
| Regent Leisure Services Limited | Wholesale & retail | 1988 |
| Regent Street Services Limited | Professional & scientific | 2005 |
| Reign Commerce Ltd | Wholesale & retail | 2024 |
| Reingold Energy Ltd | Professional & scientific | 2025 |
| Reinventar Limited | Wholesale & retail | 2024 |
| Relentless (UK) Limited | Health & social care | 2013 |
| Relish Media Ltd | Information & communication | 2025 |
| Reloyalty Limited | Information & communication | 2018 |
| REM Designs Limited | Other services | 2022 |
| Remarkable Dynamics Limited | Information & communication | 2017 |
| Remedy Hcms Ltd | Information & communication | 2007 |
| Remington Enterprise IT Ltd | Information & communication | 2014 |
| Renaissance Corporate Finance Limited | Professional & scientific | 2010 |
| Renaissance Risk Solutions Ltd | Professional & scientific | 2016 |
| Rennie Building Contracts Limited | Construction | 1981 |
| Renourish Limited | Manufacturing | 2018 |
| REO Estates and Property Investment Company Limited | Real estate | 1946 |
| Repairify UK Ltd. | Wholesale & retail | 2018 |
| Repose Gallery C.I.C. | Wholesale & retail | 2022 |
| Requity Ltd | Financial services | 2022 |
| Research for Sustainability Limited | Professional & scientific | 2008 |
| Research Park Developments Limited | Extraterritorial | 1991 |
| Research Services Limited | Professional & scientific | 2024 |
| Reserve & Charge Limited | Information & communication | 2023 |
| Reservoir Resources Ltd | Professional & scientific | 2013 |
| Residential Resources Ltd | Real estate | 2019 |
| Residents Management (NO. 55) Limited | Households | 1986 |
| Reso Limited | Wholesale & retail | 1999 |
| Resolut Limited | Professional & scientific | 2020 |
| Resonate Consult Limited | Professional & scientific | 2016 |
| Rethink Your IT Ltd | Information & communication | 2021 |
| Retrocampervan Limited | Wholesale & retail | 2013 |
| Reumat Consulting Ltd | Professional & scientific | 2016 |
| REV Developments Limited | Real estate | 2016 |
| Revelli Consulting Ltd | Professional & scientific | 2025 |
| Revenue Hub Limited | Information & communication | 2002 |
| Revilo CAB Ltd | Transport & logistics | 2017 |
| Revolutionary Limited | Professional & scientific | 2005 |
| Reynard Consultants Limited | Real estate | 2016 |
| RGS Guildford Enterprises Limited | Real estate | 2019 |
| RH Lettings Guaranteed Limited | Real estate | 2025 |
| Rhetor Communications Ltd | Information & communication | 2014 |
| RHI Heat Pumps Ltd | Construction | 2020 |
| Rhi's Hair & Beauty Limited | Other services | 2022 |
| Rhian Warner Consulting Limited | Professional & scientific | 2014 |
| Rhino Steel Construction Ltd | Construction | 2015 |
| Rhizo PTX Ltd | Professional & scientific | 2024 |
| RHM Sports Management Limited | Professional & scientific | 2021 |
| Rhone-Poulenc Rorer Holdings Limited | Professional & scientific | 1982 |
| Rhva Software Services Limited | Information & communication | 2022 |
| Rhymes Engineering Ltd | Professional & scientific | 2022 |
| Rhymes N Roses Ltd | Arts & recreation | 2020 |
| Rian Developments Limited | Construction | 2010 |