| RAB Capital Limited | Financial services | 1999 |
| Rabin Ltd | Construction | 2023 |
| Raddon Contracts Ltd | Construction | 2011 |
| Radio Gates Ltd | Extraterritorial | 2012 |
| Raeen Corporation Limited | Transport & logistics | 2016 |
| Raeen Investments Limited | Transport & logistics | 2017 |
| Rafform (Eastern) Limited | Real estate | 1978 |
| RAI Assets Limited | Professional & scientific | 2014 |
| Rail Approved Limited | Construction | 2016 |
| Rail Madrid Limited | Extraterritorial | 2015 |
| Rainbow Accounting and Consulting Ltd | Professional & scientific | 2012 |
| Ralp Holdings Limited | Real estate | 2019 |
| Ralphfibre Limited | Extraterritorial | 2024 |
| RAM Automotive Limited | | 1993 |
| RAM Trading Limited | Construction | 2020 |
| Randall Watts Construction Ltd | Construction | 2000 |
| Randall Watts Homes Limited | Construction | 2013 |
| Randall Watts Properties Limited | Construction | 2014 |
| Randhawa Homes Ltd | Real estate | 2026 |
| Rang Trading Ltd | Manufacturing | 2021 |
| Rankin Rail Ltd | Professional & scientific | 2016 |
| Ranncorp Limited | Administrative & support | 2014 |
| Ransco Limited | Professional & scientific | 2025 |
| Rapd Group Ltd | Real estate | 2026 |
| Rapid Mobile Tyres London Ltd | Wholesale & retail | 2026 |
| Rara's Childminding Ltd | Health & social care | 2025 |
| Rasasas Ltd | Real estate | 2023 |
| Rashca Limited | Professional & scientific | 2024 |
| RAT Pack Properties Ltd | Real estate | 2017 |
| Rathbone Boxing Club Limited | Arts & recreation | 2015 |
| Ratnex Limited | Information & communication | 2012 |
| RAV Singh Co Ltd | Professional & scientific | 2013 |
| Ravenscourt Park Ltd | Arts & recreation | 2018 |
| Ravenscroft Holdings Limited | Real estate | 2017 |
| Ravensharp Ltd | Information & communication | 2026 |
| Rawfell Construction Limited | Construction | 2008 |
| RAY Therm Heating Solutions Limited | Construction | 2009 |
| Raya Phuket Limited | Hospitality | 2025 |
| Rayag Limited | Other services | 2009 |
| Rayburn Properties Limited | Administrative & support | 1987 |
| Rayleigh Inns Limited | Hospitality | 2006 |
| Rayson Pharma Co. Ltd | Wholesale & retail | 2023 |
| RB Building & Properties Ltd | Construction | 2018 |
| RB Floral Design Limited | Other services | 2013 |
| RBG Contracts Limited | Construction | 2012 |
| Rbmm Education Ltd | Other services | 2012 |
| RC Boat Engines Limited | Wholesale & retail | 2024 |
| RC DE Abreu Ltd | Construction | 2012 |
| Rcbr Solutions Ltd | Hospitality | 2026 |
| Rcg-Moody International Limited | Administrative & support | 1936 |
| RCL Electrical Services Limited | Construction | 2005 |
| RD Consulting and Solutions Limited | Professional & scientific | 2023 |
| RD Plumbing & Heating Limited | Construction | 2006 |
| RDW Solutions Limited | Information & communication | 2013 |
| RE Property Group Limited | Real estate | 2025 |
| Reactive Enterprise Ltd | Wholesale & retail | 2025 |
| Reading Riverside Management Company Limited | Households | 2018 |
| Ready Services Ltd | Construction | 2022 |
| Real Bokeh Limited | Administrative & support | 2017 |
| Really Useful Business Services Limited | Professional & scientific | 2002 |
| Realtime Access (UK) Limited | Professional & scientific | 2009 |
| REALTY108 Limited | Real estate | 2024 |
| Rebuildr Group Ltd | Construction | 2025 |
| Recoil Trampoline Club Limited | Arts & recreation | 2011 |
| Recruitment Partnership Network Ltd | Administrative & support | 2015 |
| Rector Wellbeing Limited | Other services | 2019 |
| Recurve Engineering Ltd | Manufacturing | 2022 |
| Red Dimension Ltd | Professional & scientific | 2010 |
| Red Key Capital Limited | Financial services | 2016 |
| Red Tulip Ventures Greenwich Ltd | Construction | 2025 |
| Red Tulip Ventures Limited | Construction | 2025 |
| Redbine Ltd | Professional & scientific | 2019 |
| Redbox Audio Visual Limited | Wholesale & retail | 2006 |
| Redemption Light Ltd | Wholesale & retail | 2025 |
| Redhill (Investment & Development) Limited | Professional & scientific | 2007 |
| Redml Properties Limited | Real estate | 2013 |
| Redpoint Master Limited | Administrative & support | 2015 |
| Redstocks Properties Ltd | Real estate | 2022 |
| Reed Pond Properties Ltd | Construction | 2017 |
| Reed Properties Ltd | Real estate | 1996 |
| Reeve Family Partnership LLP | | 2021 |
| Referral-X Ltd | Administrative & support | 2023 |
| Refined Rarity Limited | Wholesale & retail | 2025 |
| Reflex Energy Ltd | Manufacturing | 2025 |
| Refresh Home Improvements Ltd | Construction | 2020 |
| Regal Brentwood Ltd | Administrative & support | 2023 |
| Regal Equestrian Ltd | Agriculture & fishing | 2007 |
| Regal Events Limited | Professional & scientific | 2014 |
| Regal Horizon Group Limited | Wholesale & retail | 2025 |
| Regaware.Ai Limited | Information & communication | 2025 |
| Regency Grange Residents Management Company Limited | Households | 2021 |
| Regency Green Recruitment Ltd | Administrative & support | 2024 |
| Regency Mechanical Services Ltd | Construction | 2025 |
| Reginald Developments Limited | Real estate | 2013 |
| Rehal Property Group Ltd | Real estate | 2020 |
| Reid Wilde Properties Limited | Real estate | 2017 |
| Reilley Properties Limited | Real estate | 2017 |
| Reimagined Textiles Ltd | Wholesale & retail | 2025 |
| Rekimends Limited | Administrative & support | 2024 |
| Reldon Consulting Ltd | Real estate | 2023 |