| RDL Digital Ltd | Information & communication | 2026 |
| RDL Investments Limited | Professional & scientific | 2010 |
| Rdme Ltd | Real estate | 2021 |
| Rdoc Music Ltd | Information & communication | 2025 |
| RDS Sub-Ducting and Civils Ltd | Information & communication | 2024 |
| Rdsy Limited | Hospitality | 2020 |
| RE Air Conditioning Limited | Energy | 2024 |
| RE Field Services Ltd | Manufacturing | 2004 |
| RE Skin Limited | Other services | 2022 |
| Re-Action Collective Ltd | Professional & scientific | 2022 |
| Re-Faced Ltd | Construction | 2020 |
| Re-Gen Hijama & Therapy Ltd | Health & social care | 2023 |
| Re-Vamp Builders Limited | Construction | 2017 |
| Re-Water CIC | Education | 2021 |
| Re:Happy Limited | Information & communication | 2009 |
| REA by Forge Ltd | Wholesale & retail | 2023 |
| Reach to Public Ltd | Information & communication | 2020 |
| Reachy Ltd | Wholesale & retail | 2021 |
| React Boiler Repair Ltd | Construction | 2021 |
| React Facilities Management (RFM) Ltd | Real estate | 2021 |
| React Plumbing Services Ltd | Construction | 2021 |
| Reactive Consulting Limited | Professional & scientific | 2024 |
| Reactive Plumbing Solutions Limited | Construction | 2014 |
| Read Unite Ltd | Information & communication | 2024 |
| Ready Properties Ltd | Real estate | 2024 |
| Ready Ready Go Limited | Information & communication | 2020 |
| Ready Steady Move Estate & Lettings Agents Ltd | Real estate | 2022 |
| READY2GOLOGISTIC Limited | Transport & logistics | 2025 |
| Readyfighter LP | | 2024 |
| Real Brands Group Limited | Manufacturing | 2018 |
| Real Deal Pronto Ltd | Wholesale & retail | 2021 |
| Real Deals 4 U Ltd | Wholesale & retail | 2026 |
| Real Electronics 2 Ltd | Other services | 2020 |
| Real Estate Agency Ltd | Wholesale & retail | 2007 |
| Real Freedom Investments Limited | Real estate | 2019 |
| Real Life Mortgages Limited | Financial services | 2026 |
| Real Pearl Jewellery Co Ltd | Wholesale & retail | 2021 |
| Real Pet Groomers Limited | Wholesale & retail | 2019 |
| Real Pet Grub Limited | Wholesale & retail | 2015 |
| Real Property Finance Ltd | Financial services | 2007 |
| Real Property Management Services Ltd | Professional & scientific | 2024 |
| Real Resourcing Limited | Professional & scientific | 2023 |
| Real Vibix Ltd | Wholesale & retail | 2025 |
| Real Wisdom Ltd | Professional & scientific | 2018 |
| Real World Educational Limited | Education | 2024 |
| Realcare Healthcare Ltd | Health & social care | 2020 |
| Realise Learning and Employment Holdings Limited | Financial services | 2020 |
| Realise Learning and Employment Limited | Education | 2011 |
| Realise Training Group Limited | Financial services | 2007 |
| Realise Training Holdings Limited | Financial services | 2007 |
| Realise Working Futures Limited | Financial services | 1988 |
| Really Orange Limited | Other services | 2021 |
| Realm Welding Engineers Limited | Manufacturing | 1979 |
| Reaps Wood Limited | Financial services | 2025 |
| Reash Entertainment Ltd | Professional & scientific | 2020 |
| Reason and Rhyme Music Ltd | Information & communication | 2025 |
| REB Services Ltd | Professional & scientific | 2023 |
| Reba UK Ltd | Wholesale & retail | 2021 |
| Rebalanced by Hanna Limited | Other services | 2024 |
| Rebar Minimarket Ltd | Wholesale & retail | 2025 |
| Rebecca Lockwood Ltd | Other services | 2014 |
| Rebecca Raynes Editorial Services Limited | Information & communication | 2015 |
| Rebecca Verity Aesthetics Ltd | Other services | 2025 |
| Rebel Interior Design Ltd | Professional & scientific | 2020 |
| Rebel Property Staging Limited | Administrative & support | 2024 |
| Rebell & Sons Ltd | Hospitality | 2026 |
| Rebellion BJJ Ltd | Arts & recreation | 2018 |
| Rebellious Events Ltd | Other services | 2018 |
| Reboot Cafe Ltd | Hospitality | 2024 |
| Reborn Campers Ltd | Wholesale & retail | 2021 |
| Reborn Marketer Limited | Professional & scientific | 2024 |
| Rebound Electronics (UK) Limited | Wholesale & retail | 1989 |
| Rebound Technology Group Holdings Limited | Wholesale & retail | 2003 |
| Rebound Technology Group Nominee Limited | Professional & scientific | 2024 |
| Rebus Creative Solutions Limited | Professional & scientific | 2004 |
| RECEPTION247 Ltd | Information & communication | 2020 |
| Receptive Property Limited | Real estate | 2018 |
| Reclaim Properties Ltd | Other services | 2020 |
| Reclaimed Brick & Stone Ltd | Wholesale & retail | 2021 |
| Recommended Training Group Ltd | Education | 2023 |
| Record Emporium Limited | Wholesale & retail | 2020 |
| Record Junkee Arts Community Interest Company | Arts & recreation | 2025 |
| Recordly Limited | Information & communication | 2023 |
| Recordsel Ltd | Wholesale & retail | 2026 |
| Recovery Games C.I.C. | Arts & recreation | 2026 |
| Recovery Insulation Limited | Manufacturing | 2002 |
| Recruiterclick Ltd | Information & communication | 2019 |
| Recruitment Done Simple Limited | Administrative & support | 2025 |
| Recruitsphconsultants Ltd | Administrative & support | 2020 |
| Rectory Court (Laughton) Limited | Households | 2006 |
| Recure Biotechnology & Cosmetics Limited | Manufacturing | 2022 |
| Recut Limited | Manufacturing | 2003 |
| Recx Developments Limited | Real estate | 2024 |
| Recycling Revolution | Water & waste | 2014 |
| Red Business Machines Limited | Other services | 2005 |
| Red C Consulting Limited | Information & communication | 2003 |
| Red Chili Technologies Ltd | Information & communication | 2018 |
| Red Circle Products Limited | Professional & scientific | 2000 |
| Red Citra Limited | Hospitality | 2018 |
| Red COW Nantwich Limited | Hospitality | 2022 |