| RAH RAH Properties Ltd | Real estate | 2025 |
| Rail Analytics Ltd | Professional & scientific | 2024 |
| Railsys Limited | Information & communication | 2014 |
| RAJ Shivraj Ltd | Wholesale & retail | 2020 |
| Rajari 3G Limited | Professional & scientific | 2019 |
| Ramcom Systems Limited | Professional & scientific | 2007 |
| Ramscote Health Limited | Professional & scientific | 2005 |
| Rapid Assurance Ltd | Information & communication | 2020 |
| Raroo Ltd | Wholesale & retail | 2022 |
| Rautara Services Ltd | Professional & scientific | 2022 |
| Rawlings Structural Design Ltd | Professional & scientific | 2006 |
| Rcom Solutions Ltd | Professional & scientific | 2018 |
| Rdbs Brickwork Contractors Ltd | Construction | 2020 |
| RDH Stucco Ltd | Construction | 2024 |
| Reading ARC Limited | Wholesale & retail | 2023 |
| Real Rental Ltd | Real estate | 2023 |
| Real Safety Limited | Arts & recreation | 2020 |
| Reassemblers Limited | Professional & scientific | 2013 |
| Rebecca Clark Interiors Limited | Professional & scientific | 2016 |
| Rebuild Fitness Ltd | Arts & recreation | 2026 |
| Recherche Construction Limited | Construction | 2015 |
| Recherche London Limited | Real estate | 2015 |
| Recro Consulting Limited | Administrative & support | 2009 |
| Recro Vita C.I.C. | Administrative & support | 2013 |
| Recurve Ltd | Professional & scientific | 2025 |
| Red & Black Media Limited | Information & communication | 2014 |
| Red Kite Consultants Limited | Professional & scientific | 2018 |
| Redlens Technologies Limited | Information & communication | 2026 |
| Redrum Solutions Ltd | Professional & scientific | 2024 |
| Redtile Residents Association Limited | Households | 1982 |
| Reef Resources Limited | Administrative & support | 1987 |
| Reflect Projects Ltd | Construction | 2018 |
| Reflect Windows and Doors Ltd | Construction | 2024 |
| Rege ZJB Ltd | Extraterritorial | 2022 |
| Regency Home Improvements Ltd | Construction | 2020 |
| Reinforced Recruitment Ltd | Administrative & support | 2023 |
| Reios Recruitment Ltd | Administrative & support | 2026 |
| Remark of Yhtrow Ltd | Other services | 2025 |
| Remarkable People Limited | Wholesale & retail | 2026 |
| Remcconsulting Ltd | Information & communication | 2019 |
| Renii Ltd | Information & communication | 2026 |
| RENTALS4U Limited | Administrative & support | 2015 |
| Reproductive Care Ltd | Professional & scientific | 2023 |
| Restart Training Ltd | Professional & scientific | 2020 |
| Retrofit Installations Limited | Administrative & support | 2005 |
| Revitalise Group Ltd | Other services | 2018 |
| Reviver Business Ltd | Professional & scientific | 2018 |
| REVN8 Limited | Professional & scientific | 2025 |
| Revyn Beauty Ltd | Wholesale & retail | 2025 |
| Rewound Studios Ltd | Arts & recreation | 2025 |
| Rfid Technologies Limited | Extraterritorial | 2004 |
| RFS Recovery Limited | Administrative & support | 2012 |
| RG Derma Ltd | Health & social care | 2018 |
| RH Sales & Marketing Limited | Administrative & support | 2012 |
| Rhoscolyn Rocks Property Management Ltd | Households | 2020 |
| Riak Fitness Limited | Arts & recreation | 2017 |
| Rialize Childcare Limited | Health & social care | 2019 |
| Ribbit Entertainment Limited | Information & communication | 2001 |
| Rich Roots Gardeners Ltd | Administrative & support | 2025 |
| Richard Bell DOP Limited | Information & communication | 2014 |
| Rickmansworth Vehicle Hire Ltd | Administrative & support | 2020 |
| Ridgeway Building Consultancy Limited | Construction | 2018 |
| Rights 3.0 Limited | Administrative & support | 2022 |
| Ringtail Consulting Ltd | Information & communication | 2012 |
| Rise Architects Ltd | Professional & scientific | 2011 |
| Rise Site Solutions Ltd | Administrative & support | 2021 |
| Ritchie Wrigley Limited | Professional & scientific | 2023 |
| Rive and Warner Ltd | Professional & scientific | 2020 |
| Rjhc Limited | Professional & scientific | 2021 |
| RKW Plumbing and Heating Limited | Construction | 2011 |
| RLM Building Services Ltd | Construction | 2024 |
| RM Sealers Limited | Manufacturing | 2005 |
| RMF Projects Ltd | Information & communication | 2024 |
| RML Project Delivery Services Ltd | Professional & scientific | 2026 |
| Road Maintenance (Ridgeway) Limited | Households | 1955 |
| Roar Creative Limited | Professional & scientific | 2010 |
| Roaring Great PUB Ltd | Hospitality | 2026 |
| Robert a Martell Limited | Administrative & support | 2017 |
| Robert Kane Limited | Health & social care | 2012 |
| ROC Design and Construction Ltd | Construction | 2012 |
| ROC UK Properties Ltd | Construction | 2017 |
| Rocheford Developments Ltd | Real estate | 2019 |
| Rocheford Limited | Real estate | 2023 |
| Rochester Rail Limited | Professional & scientific | 2018 |
| Rodney Clarke Associates Ltd | Administrative & support | 2026 |
| Rodney Rogers Investments Ltd | Real estate | 2019 |
| Rogue Software Limited | Information & communication | 2026 |
| Rolcom Limited | Information & communication | 2019 |
| Rooke&Sonzproperty Ltd | Construction | 2025 |
| Root 44 Limited | Other services | 2018 |
| Roots Hospitality Ltd | Hospitality | 2018 |
| Rose Garden Tea Rooms Limited | Hospitality | 2015 |
| Rosehill Management Limited | Households | 1981 |
| Rosie on Fire Ltd | Wholesale & retail | 2017 |
| Rossway Barns Management Company Limited | Households | 1989 |
| ROY Civils Limited | Construction | 2025 |
| Rpna Properties Ltd | Real estate | 2025 |
| RR & RD Properties Limited | Real estate | 2012 |
| RS Commercial Investments Ltd | Real estate | 2023 |
| RS Promo Events Ltd | Arts & recreation | 2024 |