| RDA Estates Limited | Real estate | 1993 |
| RDB Solutions Limited | Information & communication | 2008 |
| Re-Construction Eco Builds Ltd | Construction | 2025 |
| Re-Play Box Ltd | Manufacturing | 2024 |
| React Training and Communication Limited | Arts & recreation | 2006 |
| Reactive Property Services Ltd | Construction | 2016 |
| Read ALL About IT Ltd | Information & communication | 2020 |
| Ready Steady Limited | Wholesale & retail | 2012 |
| Reale Properties Limited | Real estate | 2009 |
| Realise Psychology Limited | Professional & scientific | 2008 |
| Really Wild Academy Ltd | Education | 2014 |
| Really Wild Group Limited | Extraterritorial | 2018 |
| Really Wild Tours Ltd | Administrative & support | 2022 |
| Realstreets Ltd | Professional & scientific | 2020 |
| Realworx Limited | Hospitality | 2013 |
| Rebecca Allen Estates Ltd | Real estate | 2026 |
| Rebecca Cryan Ltd | Professional & scientific | 2019 |
| Rebel Brain Ltd | Professional & scientific | 2019 |
| Rebel Property Limited | Real estate | 2019 |
| Rebel Structures Limited | Professional & scientific | 2024 |
| Rebel Waite Limited | Wholesale & retail | 2015 |
| Rebellion Nexus Ltd | Information & communication | 2025 |
| Reboundstore Limited | Wholesale & retail | 2017 |
| Rebrandr Ltd | Professional & scientific | 2023 |
| Reclaw LLP | | 2020 |
| Reco Projects Ltd | Construction | 2018 |
| Reconnaissance Music Limited | Information & communication | 2022 |
| Recoupermetal Ltd | Administrative & support | 2012 |
| Recovery Room Hove Ltd | Arts & recreation | 2025 |
| Recprotect Ltd | Information & communication | 2024 |
| Rectrix Ltd | Real estate | 2015 |
| Red Box Property and Maintenance Ltd | Construction | 2019 |
| Red Cat Creative Limited | Information & communication | 2015 |
| Red Dental-Care Ltd | Health & social care | 2014 |
| Red Door Media Ltd | Information & communication | 2012 |
| Red DOT Investments Ltd | Real estate | 2016 |
| Red Elephant Reps Ltd | Administrative & support | 2018 |
| Red Herring Films Ltd | Information & communication | 2023 |
| Red Info Ltd | Information & communication | 2022 |
| Red Kite Agency Limited | Wholesale & retail | 2017 |
| Red Marina Limited | Information & communication | 2021 |
| Red Robin PR Ltd | Professional & scientific | 2018 |
| Red Sprout Limited | Professional & scientific | 2016 |
| Red-Lan LLP | | 2012 |
| Red-Mobi LLP | | 2012 |
| Red-Net LLP | | 2013 |
| Red-Nube LLP | | 2012 |
| Redeema LLP | | 2013 |
| Redele Properties Limited | Real estate | 2022 |
| Redfern Stevens Media Limited | Professional & scientific | 2023 |
| Redhill Brewery Ltd | Manufacturing | 2024 |
| Redland Progression Limited | Professional & scientific | 2019 |
| Redlands Growth Limited | Professional & scientific | 2019 |
| Redlion Renovation and Electrical Ltd | Construction | 2022 |
| Redmire Gray Ltd | Information & communication | 2024 |
| Redpontem LLP | | 2019 |
| Redrobe Limited | Professional & scientific | 2017 |
| Reds Corner Ltd | Wholesale & retail | 2025 |
| Redspam LLP | | 2012 |
| Redspot Self Storage Limited | Real estate | 2009 |
| Redstak Technologies LLP | | 2014 |
| Redstar Works Ltd | Manufacturing | 2016 |
| Redswan Technologies LLP | | 2018 |
| Redtangle Ltd | Professional & scientific | 2006 |
| Redveu LLP | | 2014 |
| Redware Research Ltd | Information & communication | 1999 |
| Redwater Properties Limited | Real estate | 2016 |
| Redwire DC Ltd | Information & communication | 2010 |
| Redwood Consultancy Limited | Professional & scientific | 2022 |
| Redzebra Integrated Insights UK Ltd | Arts & recreation | 2006 |
| Reedminster Properties Limited | Administrative & support | 1978 |
| Reef Elec Ltd | Construction | 2017 |
| Reefsouth Limited | Real estate | 1993 |
| Reeves Social Care Limited | Health & social care | 2014 |
| Reference Design Limited | Professional & scientific | 2012 |
| Reflected Cleaning Limited | Administrative & support | 2024 |
| Reflected Detail Ltd | Manufacturing | 2022 |
| Reflection IT Limited | Information & communication | 2017 |
| Reflections (Sussex) Limited | Administrative & support | 1997 |
| Reflectv Ltd. | Wholesale & retail | 2012 |
| Refocus Education Limited | Public administration | 2026 |
| Reform Rituals Limited | Arts & recreation | 2024 |
| Reformer Collective (Brighton) Ltd | Arts & recreation | 2023 |
| Reformer Collective (Earlsfield) Ltd | Arts & recreation | 2024 |
| Reformer Collective (ES) Ltd | Arts & recreation | 2025 |
| Reformer Collective (Hove) Ltd | Arts & recreation | 2025 |
| Reformer Collective (LDN Holdings) Ltd | Arts & recreation | 2024 |
| Reformer Collective (SWL) Ltd | Arts & recreation | 2025 |
| Reformer Collective Ltd | Arts & recreation | 2023 |
| Refuel Hove Ltd | Manufacturing | 2025 |
| Regal Health Group Ltd | Health & social care | 2023 |
| Regency Corporation Limited | Hospitality | 2009 |
| Regency Integrated Solutions Ltd | Administrative & support | 2019 |
| Regency One Ltd | Real estate | 2016 |
| Regency Two Ltd | Real estate | 2017 |
| Regent & Imperial Care Limited | Real estate | 2020 |
| Regent Exhibitions Limited | Administrative & support | 2001 |
| Regent Imperial Care Limited | Financial services | 2023 |
| Regent Imperial Limited | Wholesale & retail | 2012 |
| Regents Place Residents Company Limited | Households | 1988 |