| REACT4 Plumbing Ltd | Construction | 2019 |
| Realistic Fit Limited | Education | 2024 |
| Realm Staffing Solutions Ltd | Administrative & support | 2014 |
| Realtimeworks Ltd | Information & communication | 2025 |
| Reba Care Solutions Ltd | Real estate | 2020 |
| Rebecca Cartey Ltd | Arts & recreation | 2023 |
| Rebekah Eller Ltd | Arts & recreation | 2023 |
| Rebelled Limited | Financial services | 2023 |
| Recast Digital Limited | Information & communication | 2008 |
| Receptor Healthcare Limited | Administrative & support | 2022 |
| Recooperation Limited | Information & communication | 2014 |
| Recruitcorp Ltd | Other services | 2020 |
| Red & White London Limited | Extraterritorial | 2011 |
| Red Barn Management Company Limited | Real estate | 2019 |
| Red Box Interior Solutions Limited | Administrative & support | 2014 |
| Red Box Tickets and Events Limited | Information & communication | 2015 |
| Red Box Wi-Fi Limited | Information & communication | 2023 |
| Red Brick (Stevenage) Limited | Professional & scientific | 2010 |
| Red Brick Company Secretaries Limited | Administrative & support | 2009 |
| Red Brick Freeholders Limited | Real estate | 2026 |
| Red Brick Management Limited | Households | 1998 |
| Red Chillies Ltd | Hospitality | 2015 |
| Red Europe Limited | Professional & scientific | 2008 |
| Red Flags Film Ltd | Information & communication | 2025 |
| Red Lion Limited(The) | Hospitality | 1982 |
| Red Paving Solutions Ltd | Construction | 2020 |
| Redark Multimedia Limited | Information & communication | 2017 |
| Redbrick Ashby Ltd | Professional & scientific | 2014 |
| Redd Developments Ltd | Construction | 2026 |
| Reddy Dwellings Limited | Real estate | 2021 |
| Reddys Properties Limited | Real estate | 2021 |
| Redeemed Christian Church of GOD | Other services | 2000 |
| Redeemed Christian Church of GOD City of David Stevenage | Other services | 2013 |
| Redeemed Christian Church of GOD New Life Assembly Borehamwood | Other services | 2013 |
| Redemption Hub Limited | Wholesale & retail | 2018 |
| Redhed Limited | Arts & recreation | 2003 |
| Redi Installations Ltd | Construction | 2025 |
| Redimeer Limited | Other services | 2018 |
| Redvase Limited | Real estate | 2023 |
| Red’S Roofing Ltd | Construction | 2021 |
| REE Store Limited | Water & waste | 2002 |
| Reeb Limited | Professional & scientific | 2022 |
| Reel Decor 8 FX Limited | Other services | 2014 |
| Reel Mathematical Designs Limited | Professional & scientific | 2025 |
| Reeves Creative Print & Solutions Ltd | Manufacturing | 2019 |
| Reflection Deep Cleaning Services Limited | Administrative & support | 2019 |
| Reformer Pilates Limited | Health & social care | 2024 |
| Refoveo Aesthetics Limited | Health & social care | 2013 |
| Refrigerated Van Hire Limited | Administrative & support | 2004 |
| Refrm Limited | Arts & recreation | 2023 |
| Regal Envelope and Cladding Services Ltd | Construction | 2020 |
| Regal Homes & Investments Ltd | Real estate | 2024 |
| Regal On-Site Training Ltd | Education | 2022 |
| Regal Qualifications Limited | Education | 2023 |
| Regalrose Holdings Limited | Real estate | 2020 |
| Regalrose Jewellery Limited | Manufacturing | 2012 |
| Regency Court (Enfield) Freeholders Limited | Households | 2005 |
| Regency Court (Enfield) Management Company Limited | Households | 2001 |
| Regent Secretarial Limited | Professional & scientific | 2001 |
| Rehan Capital Limited | Construction | 2022 |
| Reid Watson Consulting Limited | Professional & scientific | 2012 |
| Reign of Beauty Ltd | Other services | 2026 |
| Relaunch Your Career Ltd | Extraterritorial | 2009 |
| Relentless People Ltd | Information & communication | 2025 |
| Reliable Electrical Engineering Solutions Limited | Construction | 2015 |
| Reliable Equity Solutions Limited | Financial services | 2009 |
| Reliance Plumbing and Heating Ltd | Administrative & support | 2025 |
| Relish Projects Limited | Professional & scientific | 2024 |
| Relocare Medical Limited | Administrative & support | 2025 |
| Relocate Home 4 Home Rentals Ltd | Hospitality | 2022 |
| Relto Limited | Hospitality | 2026 |
| Remedy Fulfilment (UK) Limited | Transport & logistics | 2014 |
| Remflo Ltd | Other services | 2017 |
| Remington Trading Limited | Wholesale & retail | 2025 |
| Remiz Care & Recruitment Services Ltd | Administrative & support | 2014 |
| RENAISSANCE26 Ltd | Wholesale & retail | 2020 |
| Renegade Combat Academy Limited | Arts & recreation | 2024 |
| Renji Services Limited | Health & social care | 2025 |
| RENOVATE2RECREATE Ltd | Construction | 2025 |
| Rent Away Ltd | Real estate | 2018 |
| Rent OUT Ltd | Real estate | 2021 |
| Renzel Industries Limited | Wholesale & retail | 2024 |
| Rephine Bidco Limited | Administrative & support | 2021 |
| Rephine Limited | Professional & scientific | 2001 |
| Rephine Midco Limited | Administrative & support | 2021 |
| Rephine Topco Limited | Administrative & support | 2021 |
| REPORTS4HOMES Ltd | Professional & scientific | 2025 |
| Reselloo Ltd | Wholesale & retail | 2026 |
| Reside Refurbishment Consultancy Ltd | Construction | 2024 |
| Reside Residential Developments Ltd | Real estate | 2024 |
| Residents Association of Welwyn Heath Limited | Other services | 2011 |
| Resistance Fire and Security Systems Limited | Administrative & support | 2013 |
| Resistance Property Investments Ltd | Real estate | 2022 |
| Responsive TV Limited | Information & communication | 2015 |
| Restorepoint Ltd | Information & communication | 2008 |
| Retina Macula UK Limited | Professional & scientific | 2016 |
| Retro Media Bushey Limited | Education | 2017 |
| Reunion Properties Limited | Real estate | 2001 |
| Revenage Ltd | Professional & scientific | 2020 |
| Revenues Solutions Ltd | Administrative & support | 2025 |