| Rabbit Investments Limited | Real estate | 2004 |
| Rabochii Klass Limited | Real estate | 2020 |
| RAD CS Ltd | Health & social care | 2025 |
| Radpass Ltd | Professional & scientific | 2025 |
| Radsolve Ltd | Information & communication | 2026 |
| RAE Architecture Limited | Professional & scientific | 2026 |
| RAG Entertainment Limited | Arts & recreation | 2024 |
| Ragtel Properties Ltd | Real estate | 2025 |
| Raidius Vision Ltd | Wholesale & retail | 2002 |
| Raigad Consulting Ltd | Information & communication | 2022 |
| Rainbow Rainforest Ltd | Professional & scientific | 2019 |
| Raincloud UK Limited | Extraterritorial | 2017 |
| RAK Property Developments Limited | Real estate | 2017 |
| Rakshana Ltd | Wholesale & retail | 2024 |
| Ralli Property Ltd | Construction | 2023 |
| Rama Dasani Ltd | Real estate | 2025 |
| Ramko Tech Consulting Ltd | Information & communication | 2026 |
| Rammo Sets UK Ltd | Construction | 2024 |
| Ramornie Agriculture Ltd | Agriculture & fishing | 2025 |
| Rani Capital Limited | Real estate | 2020 |
| Rapha Sanctuary Ltd | Health & social care | 2011 |
| Rapid Security Solutions Ltd | Administrative & support | 2019 |
| Rata Ltd | Hospitality | 2024 |
| Ravenhunter Ltd | Wholesale & retail | 2014 |
| Ravinium Ltd | Information & communication | 2010 |
| Ravish Technologies Limited | Information & communication | 2013 |
| RAY Nine Ltd | Wholesale & retail | 2020 |
| Rayarel Group Ltd | Financial services | 2025 |
| Razor Performance Ltd | Health & social care | 2024 |
| RB Assets Ltd | Real estate | 2022 |
| RC IT Consultancy Limited | Information & communication | 2010 |
| RCI Bank UK Limited | Financial services | 2018 |
| RCI Financial Services Limited | Financial services | 1997 |
| RD Spa Limited | Health & social care | 2025 |
| RDB Property Investments Ltd | Construction | 2019 |
| Rdbpi Freehold Limited | Households | 2022 |
| Rdbpi Regency Apartments Ltd | Real estate | 2024 |
| REA Retail Limited | Other services | 2019 |
| Reach Learning Limited | Education | 2010 |
| Reach London Limited | Real estate | 2007 |
| Reach OUT Cafe CIC | Hospitality | 2023 |
| Reaching Art Limited | Professional & scientific | 2024 |
| Reactive Systems Consulting Limited | Information & communication | 2015 |
| Ready Care Limited | Real estate | 2020 |
| Ready Care Services Limited | Administrative & support | 2018 |
| Reality Jump Ltd | Information & communication | 2023 |
| Reartion Limited | Education | 2024 |
| Reblox Ltd | Real estate | 2025 |
| Reclamonic Comics Ltd | Wholesale & retail | 2025 |
| Reconnect Consulting Services Ltd | Information & communication | 2022 |
| Recubed Ltd | Information & communication | 2026 |
| Recula Limited | Wholesale & retail | 2025 |
| Recycling Clothes Company Limited | Water & waste | 2008 |
| Red Amaranth Ltd | Other services | 2023 |
| Red Jelli Technology Limited | Information & communication | 2013 |
| Red Lemon Logistics Ltd | Transport & logistics | 2023 |
| Red Line Consulting Ltd | Professional & scientific | 2018 |
| Red Soil Ltd | Health & social care | 2017 |
| Redbrick Tutors Ltd | Education | 2024 |
| Redhorn Corporation Limited | Professional & scientific | 2016 |
| Redhorn Emea Limited | Professional & scientific | 2016 |
| Reel Figures Ltd | Information & communication | 2010 |
| Reevanav Limited | Wholesale & retail | 2020 |
| Refah Ltd | Real estate | 2015 |
| Reframe Consent and Workplace Training Limited | Professional & scientific | 2024 |
| Regal Outfit Ltd | Other services | 2024 |
| Regency Foundation Networx | Education | 1998 |
| Regency Resource Limited | Administrative & support | 1994 |
| Regent Home Care (West Herts) Ltd | Health & social care | 2008 |
| Regent Home Care Limited | Health & social care | 2019 |
| Regent Projects Limited | Construction | 2005 |
| Rehaulage Limited | Water & waste | 2022 |
| Reky Limited | Manufacturing | 2021 |
| REL Staff Services Limited | Administrative & support | 2018 |
| Relativity Intelligent Marketing Limited | Professional & scientific | 2014 |
| Relaunch Global Ltd | Administrative & support | 2025 |
| Rely Properties Limited | Real estate | 2021 |
| Renault U.K. Limited | Wholesale & retail | 1904 |
| Renewable Power Projects Limited | Administrative & support | 2011 |
| Rennie & Buxton Legal Ltd | Professional & scientific | 2026 |
| Rennie & Buxton Legal Services LLP | | 2022 |
| Rensburg PTY Ltd | Health & social care | 2008 |
| Residential Design & Build Ltd | Construction | 2019 |
| Residents Management (17 Adamson Road) Limited | Real estate | 1986 |
| Resolve Works Limited | Other services | 2024 |
| Resourceful Renovations Ltd | Real estate | 2024 |
| Resourceful.Ai Ltd | Information & communication | 2025 |
| Retro Romance Boutique Ltd | Wholesale & retail | 2019 |
| Retro Towers Ltd | Wholesale & retail | 2021 |
| Returnshare Property Management Limited | Real estate | 1993 |
| Revacc Consultants Ltd | Professional & scientific | 2010 |
| REVISION4U Limited | Education | 2011 |
| Revive Physio Centre Ltd | Health & social care | 2024 |
| Revive YOU Limited | Arts & recreation | 2022 |
| Rexvar Capital Ltd | Financial services | 2024 |
| RGE Events Limited | Arts & recreation | 2019 |
| Rhythm Life Ltd | Wholesale & retail | 2025 |
| Riaz Solutions Limited | Real estate | 2023 |
| Ricardo DE SA Ltd | Professional & scientific | 2013 |
| Richard Philbert Limited | Information & communication | 2012 |