| Raygun Creative Limited | Professional & scientific | 2013 |
| Raymond YAU Limited | Professional & scientific | 2016 |
| Raymond's Reliable Refurbishments Ltd | Construction | 2025 |
| Razor Sharp Mens Barbering and Grooming Ltd | Other services | 2012 |
| Razor Systems Limited | Information & communication | 2026 |
| Rb&As Consultants Limited | Information & communication | 2009 |
| RBC Builders Limited | Construction | 2023 |
| RBK Services Ltd | Wholesale & retail | 2001 |
| RBS Pro Ltd | Other services | 2024 |
| RBW Design and Production Limited | Administrative & support | 2012 |
| RCI Trading Limited | Wholesale & retail | 2012 |
| Rcmc Limited | Real estate | 2016 |
| Rcmr Solutions Limited | Information & communication | 2013 |
| RCS Developers Ltd | Real estate | 2015 |
| Rcsl Homes Limited | Real estate | 2024 |
| RD Childcare Limited | Hospitality | 2004 |
| RD Garden Maintenance Limited | Administrative & support | 2026 |
| RDF Waste Limited | Water & waste | 2013 |
| RDL Rescue Limited | Other services | 2025 |
| RDM Builders Limited | Construction | 2016 |
| RDM Talent Management Ltd | Professional & scientific | 2022 |
| RDS Hardware Ltd | Wholesale & retail | 2024 |
| REA Technologies UK Limited | Information & communication | 2022 |
| Rea-Vr Ltd | Information & communication | 2022 |
| Reachout Global | Other services | 2020 |
| Real Eazy Limited | Manufacturing | 2022 |
| Real Estate Beyond 2050 Ltd | Construction | 2021 |
| Real Fortunes Limited | Real estate | 2025 |
| Real Work Ltd | Construction | 2025 |
| Real-Time Resources Limited | Information & communication | 1996 |
| Realce Limited | Professional & scientific | 2004 |
| Realgold Developments Limited | Real estate | 2016 |
| Realgold Investments Limited | Real estate | 2000 |
| Realm Fire Ltd | Construction | 2023 |
| Realm Investment Research LLP | | 2008 |
| Realty Experts Limited | Real estate | 2017 |
| Rebalance Systems Limited | Professional & scientific | 2012 |
| Rebecca Collins Smile Ltd | Health & social care | 2015 |
| Rebeccadidmyhair Ltd | Other services | 2024 |
| Recognition Media Ltd | Information & communication | 2019 |
| Recording Earth Ltd | Information & communication | 2013 |
| RECOVER360 Ltd | Health & social care | 2026 |
| Recovery Focused Care Ltd | Health & social care | 2022 |
| Rectory Road Management Limited | Households | 1965 |
| Red Bear Digital Ltd | Information & communication | 2016 |
| Red Heat Ltd | Construction | 2022 |
| Red Manta Ltd | Information & communication | 2006 |
| Red Phoenix Films Ltd | Information & communication | 2019 |
| Red Phoenix Property Solutions Limited | Real estate | 2025 |
| Red Ribbon Living Well CIC | Health & social care | 2022 |
| Red Veil Limited | Hospitality | 2026 |
| Redchurch (London) Brewery Ltd | Manufacturing | 2019 |
| Redinet Holdings Ltd | Wholesale & retail | 2019 |
| Redinet Limited | Information & communication | 1998 |
| Redinet Voice and Data Ltd | Information & communication | 2019 |
| Redland Tandoori (Bristol) Ltd | Hospitality | 2012 |
| Redmans Road RTM Company Limited | Households | 2013 |
| Redpanda Care Limited | Wholesale & retail | 2020 |
| Redsun Enterprise Limited | Extraterritorial | 2013 |
| Redtarn Properties Ltd | Real estate | 2021 |
| Redwood Green Energy Holdings Limited | Financial services | 2025 |
| Redwood Green Energy Limited | Financial services | 2025 |
| Reece Thomas Watson Limited | Professional & scientific | 2015 |
| Reef Investments Ltd | Real estate | 2019 |
| Reena Pathak Ltd | Education | 2026 |
| Rees Refrigeration Limited | Manufacturing | 2005 |
| Refind SW11 Ltd | Wholesale & retail | 2021 |
| Refined Security Ltd | Administrative & support | 2025 |
| Refino Bakery Ltd | Wholesale & retail | 2022 |
| Refocus Project Ltd | Education | 2012 |
| Reform Building & Maintenance Limited | Administrative & support | 2016 |
| Refreshers Ltd | Wholesale & retail | 2011 |
| Regal III Ltd | Real estate | 2020 |
| Regal Ride Services Limited | Transport & logistics | 2025 |
| Regalinfluence Ltd | Administrative & support | 2023 |
| Regency Drive Management Company Limited | Real estate | 2013 |
| Regency Gate (Berkhamsted) Management Limited | Households | 2002 |
| Regency Management Services Ltd | Real estate | 2002 |
| Regent Locksmith Limited | Other services | 2018 |
| Regenta Properties Group Ltd | Real estate | 2025 |
| Regents Canal House Limited | Households | 1996 |
| Regimentals Vintage Clothing Limited | Wholesale & retail | 2001 |
| Regina Accounts Ltd | Professional & scientific | 2013 |
| Regis Park Management Company Limited | Households | 1992 |
| Regro Earth Ltd | Information & communication | 2023 |
| Reigate Manor Limited | Hospitality | 2025 |
| Rekruuto Ltd | Information & communication | 2021 |
| Relakstyle Ltd | Wholesale & retail | 2017 |
| Reliable Community Care Services Ltd. | Health & social care | 2020 |
| Reliable Recovery Ltd | Transport & logistics | 2020 |
| Reliable Services Group Ltd | Construction | 2021 |
| Reliance VAC Spares(Bexley Heath)Limited | Real estate | 1947 |
| Reloved Treasures Ltd | Wholesale & retail | 2024 |
| Relyo Ltd | Professional & scientific | 2026 |
| Remian Group UK Limited | Financial services | 2025 |
| Remian UK Limited | Construction | 2024 |
| Remotedesk UK Limited | Information & communication | 2019 |
| Remvision Limited | Arts & recreation | 1995 |
| Renaissance 72 Limited | Real estate | 2018 |
| Renaissance Designs Construction Ltd | Construction | 2022 |