| Reel Millinery Limited | Administrative & support | 2015 |
| Reem Investments Ltd | Real estate | 2019 |
| Reflective Valeting & Detailing Limited | Administrative & support | 2016 |
| Regalis Labs Ltd | Wholesale & retail | 2024 |
| Regans Carpentry Limited | Manufacturing | 2021 |
| Regency Construction (London) Limited | Construction | 2020 |
| Regency Registrars Limited | Professional & scientific | 1983 |
| Regent Automatic Machines Limited | Administrative & support | 2004 |
| Regent Garage Restoration Limited | Wholesale & retail | 2019 |
| Regrisk Technology Limited | Financial services | 2019 |
| Regulativ.Ai Ltd | Information & communication | 2020 |
| REL (Epsom) Limited | Construction | 2026 |
| REL (Kingston) Limited | Construction | 2026 |
| Relicnexa Ltd | Information & communication | 2026 |
| REM Services 2015 Limited | Real estate | 2015 |
| Remedi Laser Ltd | Other services | 2020 |
| Remedi Training Academy Ltd | Other services | 2022 |
| Remline Ltd | Wholesale & retail | 2026 |
| Remont UK Limited | Construction | 2000 |
| Renae Media Ltd | Information & communication | 2018 |
| Render Goods Ltd | Wholesale & retail | 2023 |
| Rengineers Limited | Construction | 2015 |
| Rent With US Limited | Real estate | 2018 |
| RER Deptford Project Management Limited | Real estate | 2023 |
| RER Deptford Promote Holdings Limited | Financial services | 2024 |
| RER Deptford Promote Limited | Other services | 2024 |
| RER Deptford Sponsor Holdings Limited | Financial services | 2024 |
| RER Deptford Sponsor Limited | Other services | 2024 |
| RER Holdings Limited | Financial services | 2015 |
| RER London Limited | Construction | 2009 |
| RER Project Management Limited | Real estate | 2010 |
| RES Sky Ltd | Information & communication | 2026 |
| Rescura Ltd | Information & communication | 2002 |
| Resilience Care Solutions Limited | Administrative & support | 2021 |
| Resilience Personnel Ltd | Administrative & support | 2015 |
| Resound Events Ltd | Administrative & support | 2019 |
| Retail Search Solutions Ltd | Professional & scientific | 2010 |
| Retrüv Ltd | Information & communication | 2026 |
| Revicta Limited | Information & communication | 2015 |
| Reviewer Limited | Information & communication | 1999 |
| Revitope Auto Immune Limited | Professional & scientific | 2024 |
| Revitope Limited | Professional & scientific | 2014 |
| Revival Racing Limited | Wholesale & retail | 2014 |
| Revive Health and Fitness Ltd | Arts & recreation | 2022 |
| Rexell UK Limited | Wholesale & retail | 2024 |
| Rezurvit Ltd | Information & communication | 2015 |
| RG Kingsmead Management Company Limited | Households | 2017 |
| RGP Construction Ltd | Administrative & support | 2016 |
| Rhapsody Photographic Limited | Wholesale & retail | 1999 |
| RHB Group Ltd | Construction | 2022 |
| RHB Industrial Ltd | Real estate | 2025 |
| Rhybels Holding Ltd | Financial services | 2023 |
| Rhyzen Production Limited | Wholesale & retail | 2021 |
| Richard Lehane Limited | Wholesale & retail | 2022 |
| Richmond Financial Solutions Ltd | Financial services | 2019 |
| Rick Training Limited | Other services | 2023 |
| Ridge Marketing Limited | Information & communication | 2015 |
| Ridgeback Investments Ltd | Administrative & support | 2016 |
| Ridings Lodge (Enfield) Management Limited | Households | 1965 |
| Right Living Ltd | Real estate | 2024 |
| Rigoletto Services Ltd | Administrative & support | 2018 |
| Rika 13 Ltd | Administrative & support | 2015 |
| Rina Prime Value Services International Ltd | Professional & scientific | 2023 |
| Rinmore Limited | Real estate | 2024 |
| Rione Properties Ltd | Real estate | 2020 |
| Rise 360 Limited | Information & communication | 2011 |
| Rise International Music Limited | Information & communication | 1995 |
| Rise Utilities Ltd | Construction | 2024 |
| Riverbridge Landscapes Limited | Other services | 2018 |
| Riverdale Music Ltd | Information & communication | 2026 |
| Rivulet Holiday Park Ltd | Hospitality | 2025 |
| Rizal and Dhital Private Ltd | Real estate | 2020 |
| RJ Tradng Ltd | Hospitality | 2025 |
| Rjbman Limited | Arts & recreation | 2013 |
| RK67 Limited | Administrative & support | 2020 |
| Rkpro Services Ltd | Information & communication | 2016 |
| RM UK Construction Ltd | Construction | 2024 |
| RMM Property Ltd | Real estate | 2017 |
| RMP Commercial Services Ltd | Professional & scientific | 2026 |
| RMP Consultancy Limited | Construction | 2009 |
| RO 101 Limited | Extraterritorial | 2005 |
| RO 103 Limited | Professional & scientific | 2014 |
| RO Beachampton Limited | Construction | 2019 |
| RO Bowhays Limited | Energy | 2026 |
| RO Capital Partners Limited | Professional & scientific | 2014 |
| RO Chichester Limited | Construction | 2017 |
| RO Connect 2017 Limited | Professional & scientific | 2017 |
| RO Connect 2023 Limited | Financial services | 2023 |
| RO Cornwall Limited | Professional & scientific | 2019 |
| RO Hub Ltd | Wholesale & retail | 2025 |
| RO Investments Limited | Professional & scientific | 2011 |
| RO Properties Limited | Construction | 2004 |
| RO Property Management Limited | Construction | 1966 |
| RO Regional Properties Limited | Construction | 2002 |
| RO Ryeford Limited | Energy | 2026 |
| RO Solstice Limited | Construction | 2019 |
| RO ST Bernards Limited | Construction | 2004 |
| RO ST Leonards Limited | Administrative & support | 2019 |
| RO Trading Limited | Financial services | 2004 |
| RO Transport Ltd | Transport & logistics | 2025 |