| RD Auto Diagnostics Ltd | Wholesale & retail | 2024 |
| RD Business Consulting UK Ltd | Professional & scientific | 2025 |
| RDA Jewellers Ltd | Wholesale & retail | 2026 |
| RDD Painters & Decorators Ltd | Construction | 2012 |
| RDJ Reptiles Ltd | Education | 2023 |
| RDJ Rescue & Rehoming CIC | Other services | 2025 |
| RDS Business Management Ltd | Professional & scientific | 2020 |
| RDS Roadsport Limited | Wholesale & retail | 2012 |
| Re-Gen Aggregate and Concrete Ltd | Construction | 2025 |
| React Medical Limited | Health & social care | 2003 |
| React Recruitment Limited | Administrative & support | 1999 |
| Reactive Action Ltd | Administrative & support | 2025 |
| Read With US Ltd | Education | 2020 |
| Reader Security Consultancy (RSC) Ltd | Administrative & support | 2025 |
| Readycrest Limited | Information & communication | 1989 |
| Readycrest Networks Limited | Extraterritorial | 1998 |
| Readycrest Services Limited | Extraterritorial | 2013 |
| Readysip Limited | Extraterritorial | 2017 |
| Realgar Limited | Professional & scientific | 2018 |
| Rebecca Collins Virtual Assistant Ltd | Administrative & support | 2014 |
| Recharged Media Limited | Arts & recreation | 2010 |
| Recroutons / Recruitons Limited | Administrative & support | 2017 |
| Recycled Roadways Limited | Water & waste | 2003 |
| Red Flame GAS Services Ltd | Construction | 2019 |
| Red Mountain Assets Ltd | Real estate | 2020 |
| Red Point Fire Protection Ltd | Construction | 2025 |
| Red Project Services Limited | Administrative & support | 2013 |
| Red Tree Apartments Ltd | Households | 2018 |
| Red Triangle Health Ltd. | Wholesale & retail | 2015 |
| Redcrunch Ltd | Wholesale & retail | 2024 |
| Reddoor Homes Ltd | Real estate | 2010 |
| Reddoor Homes Rochester Ltd | Real estate | 2013 |
| Redeemed Christian Church of GOD Victorious Family Parish | Professional & scientific | 2013 |
| Redriffe Management Company Limited | Households | 2019 |
| Reds Recovery Limited | Wholesale & retail | 2025 |
| Redstone Recruitment (UK) Ltd | Administrative & support | 2024 |
| Redwalls (Residents) Management Company Ltd | Households | 2025 |
| Reeds Financial Limited | Financial services | 2020 |
| Reel Wonders Production Ltd | Information & communication | 2024 |
| Rees Mellish (Holdings) Limited | Financial services | 2015 |
| Rees Mellish Hotel Management Limited | Other services | 2016 |
| Rees Mellish Limited | Other services | 2009 |
| Refill&Nourish Ltd | Wholesale & retail | 2025 |
| Refined Insight Ltd | Information & communication | 2018 |
| Reform+Reset Ltd | Arts & recreation | 2025 |
| Refractory Maintenance & Boiler Industrial Services Limited | Construction | 2005 |
| Regal Harti Renovation Ltd | Construction | 2023 |
| Regal Land and Developments Limited | Real estate | 2019 |
| Regal Range Properties Limited | Real estate | 2024 |
| Regal Range Property Management Limited | Real estate | 2019 |
| Regal Scaffolding Limited | Administrative & support | 2006 |
| Regalcove Limited | Other services | 2019 |
| Regalia LDN Jewellery Ltd | Wholesale & retail | 2025 |
| Rehoboth Business Services Ltd | Financial services | 2022 |
| Rehoboth Venturesuk Ltd | Wholesale & retail | 2026 |
| Rehobothd Group Holdings Ltd | Professional & scientific | 2026 |
| Rehobothone Ltd | Real estate | 2025 |
| Reign Care Limited | Health & social care | 2022 |
| Reit Property Investment Ltd | Real estate | 2021 |
| Rellaw Services Limited | Administrative & support | 2017 |
| Rellish Ashford Limited | Construction | 2017 |
| Rellish Facilities Management Limited | Other services | 2005 |
| Rellish Ludlow House Ltd | Real estate | 2014 |
| REM Haus Enterprises Ltd | Real estate | 2025 |
| Remanx Ltd | Other services | 2023 |
| Remet Real Estate Holding UK Ltd | Financial services | 2020 |
| Remet Riverside Limited | Real estate | 2014 |
| Remet UK Limited | Manufacturing | 2003 |
| Remet Whitewall Limited | Real estate | 2014 |
| Remmywealth Kitchen Ltd | Hospitality | 2025 |
| Remoraa Jewellery Limited | Wholesale & retail | 2023 |
| Renah Group Ltd | Administrative & support | 2024 |
| Renaissance Construction Limited | Construction | 2025 |
| Renaissance of London Limited | Construction | 2014 |
| Render-Vate Limited | Construction | 2023 |
| Rennor Properties Ltd | Real estate | 2016 |
| Rennu Consultancy Ltd | Health & social care | 2018 |
| Reps & Sets Limited | Arts & recreation | 2015 |
| Reptile Promotions Ltd | Arts & recreation | 2023 |
| Reserve NOW Limited | Information & communication | 2025 |
| Residential Marine Ltd. | Hospitality | 1974 |
| Resiliance Ltd | Administrative & support | 2018 |
| Resin Contracts Ltd | Administrative & support | 2017 |
| Resin Monkey Business Limited | Manufacturing | 2020 |
| Resolve Bookkeeping Ltd | Professional & scientific | 2021 |
| Resolve Electrical & Controls Ltd | Construction | 2026 |
| Respect Safety Ltd | Professional & scientific | 2018 |
| Rest a While Cafe Ltd | Hospitality | 2019 |
| Rest Delights Treat Ltd | Administrative & support | 2025 |
| Restauracion CIC | Other services | 2016 |
| Reuse Access Floors Ltd | Construction | 2025 |
| REV IQ Automotive Ltd | Wholesale & retail | 2025 |
| Revelation Permanent Make UP Ltd | Other services | 2021 |
| Revere Property Renovations Ltd | Construction | 2026 |
| Revive Force Ltd | Administrative & support | 2026 |
| Revolution Agency Ltd | Information & communication | 2014 |
| Revulv Ltd | Information & communication | 2023 |
| Revyve Ltd | Professional & scientific | 2015 |
| REY Healthcare Services Ltd | Administrative & support | 2023 |
| Reydom Accounting and Tax Ltd | Professional & scientific | 2025 |