| Quantumquake IT Limited | Information & communication | 2025 |
| Qube Financial Consulting Ltd | Professional & scientific | 2023 |
| Quera Computing UK Limited | Professional & scientific | 2023 |
| Quinton Maintenance Services Limited | Manufacturing | 2009 |
| Qustream Ltd | Information & communication | 2025 |
| R & D Creative Limited | Professional & scientific | 2011 |
| R Boxall Ltd | Financial services | 2024 |
| R J Frost Limited | Hospitality | 2005 |
| R J Produce Ltd | Wholesale & retail | 2025 |
| R L Automotive Limited | Wholesale & retail | 2000 |
| R&R Construction Oxfordshire Ltd | Construction | 2025 |
| R1GHT Investments Limited | Real estate | 2026 |
| R1GHT Property Limited | Real estate | 2026 |
| RA Research Ltd | Professional & scientific | 2026 |
| Raco Ventures Ltd | Real estate | 2020 |
| Radi Ralev Ltd | Health & social care | 2021 |
| Radley Windows Limited | Construction | 1983 |
| RAM & Sons Construction Ltd | Construction | 2025 |
| RAM Brand Ltd | Arts & recreation | 2023 |
| RAM Electrical Services Ltd | Construction | 2017 |
| Ranalysed Ltd | Professional & scientific | 2024 |
| Rapid Diagnostics ML Limited | Other services | 2017 |
| Rapt Consultancy Ltd | Professional & scientific | 2025 |
| Rbmho Trust Corporation Limited | Administrative & support | 2018 |
| RBW Scaffolding Limited | Administrative & support | 2021 |
| Rdjah Investments Ltd | Real estate | 2025 |
| Reading Ukrainian School Lastivka C.I.C. | Education | 2025 |
| Reama Security Solutions Ltd | Administrative & support | 2019 |
| Recover and Thrive Ltd | Information & communication | 2026 |
| Recruitment Solutions (Services) Ltd | Administrative & support | 2008 |
| Recursivesoft Limited | Information & communication | 2013 |
| Red Dog Estates Ltd | Real estate | 2019 |
| Red Iceberg Ltd | Real estate | 2025 |
| Red Semiconductor International Ltd | Manufacturing | 2018 |
| Redding Group Ltd | Real estate | 2025 |
| Redgear Motorsport UK Ltd | Wholesale & retail | 2025 |
| Redwood Carpentry and Joinery Ltd | Construction | 2020 |
| Reflex Property Holdings Limited | Financial services | 2025 |
| Reflex Property Investments Limited | Real estate | 2025 |
| Reflex Property Solutions Limited | Real estate | 2025 |
| Regency Partners Ltd | Transport & logistics | 2023 |
| Reiga Estates Ltd | Real estate | 2020 |
| Reinvent Infotech Ltd | Information & communication | 2019 |
| Relair Limited | Wholesale & retail | 2023 |
| Reliq IT Ltd | Information & communication | 2019 |
| Remote Living Ltd | Real estate | 2021 |
| Rendel VON VEH Holdings Limited | Real estate | 2019 |
| Rendezvous Sound Ltd | Information & communication | 2025 |
| Research Data Alliance Foundation | Professional & scientific | 2014 |
| Resmed (UK) Limited | Wholesale & retail | 1993 |
| Resmed EPN Ltd | Wholesale & retail | 2009 |
| Resmed European Holdings Limited | Financial services | 2013 |
| Resmed Global Holdings Ltd. | Financial services | 2018 |
| Resmed Sleep Solutions Limited | Wholesale & retail | 2014 |
| Resterra Limited | Financial services | 2014 |
| Restorative Justice Publishing Ltd | Other services | 2026 |
| Reverence Health Group Ltd | Wholesale & retail | 2026 |
| Revive Medical Limited | Financial services | 2009 |
| Reward Tech Limited | Manufacturing | 2021 |
| Reward Technologies Ltd | Manufacturing | 2023 |
| Richard Jeremy Consulting Limited | Professional & scientific | 2014 |
| Rickstone Property Consulting Ltd | Construction | 2021 |
| Rico Medical UK Ltd | Manufacturing | 2022 |
| Rico Solutions Limited | Real estate | 2015 |
| Ricoed Global Ltd | Wholesale & retail | 2022 |
| Ridgeway Agricultural Services Limited | Agriculture & fishing | 2020 |
| Ridgeway Coaching Limited | Professional & scientific | 2020 |
| Ridgeway Education Trust | Education | 2012 |
| Ridgeway Kite Software Limited | Information & communication | 2013 |
| Ridgeway Property Services (Oxon) Limited | Construction | 2018 |
| Rightway Building Contractors Limited | Construction | 2014 |
| Riot Creative Limited | Professional & scientific | 2025 |
| Rising Edge Capital Ltd | Real estate | 2024 |
| Riverbank Adventure Ltd | Arts & recreation | 2021 |
| RKC Design Studio Limited | Professional & scientific | 2018 |
| RKG Driveways & Landscaping Ltd | Construction | 2024 |
| RL Capital Limited | Wholesale & retail | 1998 |
| RMT Express Ltd | Wholesale & retail | 2022 |
| Road Trukxify Ltd | Construction | 2025 |
| Roadtorecovery Ltd | Health & social care | 2024 |
| Roberts-Lock Consulting Ltd | Information & communication | 2025 |
| Rocket Dog Properties Ltd | Real estate | 2021 |
| Rocket Insight Limited | Information & communication | 2024 |
| Rohan Real Estates Limited | Real estate | 2020 |
| ROJ Bkbl Limited | Hospitality | 2025 |
| ROJ FB Ltd | Hospitality | 2022 |
| Rojek Limited | Real estate | 2024 |
| Ronco Consulting Ltd | Information & communication | 2026 |
| Roohi Limited | Professional & scientific | 2013 |
| Roselin Medical Ltd | Manufacturing | 2022 |
| Rosh Capital Ltd | Real estate | 2025 |
| Rosi NI Bolatagane Ltd | Wholesale & retail | 2026 |
| Rowstock Limited | Wholesale & retail | 1986 |
| Rowstock Properties Limited | Real estate | 2003 |
| Roylepriest Care Limited | Health & social care | 2024 |
| Roysperfection Ltd | Hospitality | 2019 |
| Rpmg Ltd | Professional & scientific | 2023 |
| RR Testing Services Ltd | Information & communication | 2014 |
| RR7 Investments Limited | Financial services | 2024 |
| Rtech Associates Ltd | Information & communication | 2014 |