| Retroid Ltd | Information & communication | 2023 |
| Retrosure Ltd | Public administration | 2022 |
| Retrotrade Ltd | Information & communication | 2012 |
| Revadd Limited | Information & communication | 2012 |
| Revadd Properties Ltd | Real estate | 2021 |
| Revel Consulting Ltd | Professional & scientific | 2023 |
| Revere Brands Limited | Other services | 2012 |
| Revere Clinics Ltd | Other services | 2015 |
| Revere HT Limited | Health & social care | 2020 |
| Revere Skin Limited | Other services | 2011 |
| Revere Transport Ltd | Transport & logistics | 2016 |
| Revival Health Care Limited | Health & social care | 2017 |
| Revive Events Ltd | Other services | 2025 |
| Revive Skin Studio by Annmarie Ltd | Health & social care | 2025 |
| Revivo Surgery Ltd | Health & social care | 2024 |
| Revolution Seals & Bearings Limited | Wholesale & retail | 1978 |
| Revolutionary Music Ltd | Information & communication | 2025 |
| Revolutionary Records Ltd | Information & communication | 2025 |
| Reward Heads Limited | Professional & scientific | 2013 |
| Rewaris Limited | Professional & scientific | 2025 |
| Rexport Construction LP | | 2019 |
| Reynolds Insulation Solutions Ltd | Construction | 2018 |
| Reysons Ltd | Wholesale & retail | 2026 |
| RF Surveyors Ltd | Professional & scientific | 2017 |
| RF Training Limited | Transport & logistics | 2015 |
| RFC Watford Ltd | Wholesale & retail | 2024 |
| RFI Foundation C.I.C. | Other services | 2015 |
| RFM Associates Accountants LLP | | 2021 |
| Rfvvl Ltd | Wholesale & retail | 2024 |
| RG Interpreting Ltd | Professional & scientific | 2024 |
| RG UK Properties Limited | Real estate | 2021 |
| RGB Estates Ltd | Real estate | 2025 |
| RGC Investment Holdings Ltd | Financial services | 2020 |
| RGF Investments Limited | Information & communication | 2019 |
| RGI Properties Ltd | Construction | 2017 |
| RGL Construction Services Ltd | Construction | 2020 |
| RH & Sons Ltd | Transport & logistics | 2018 |
| RHD GAS & Plumb Ltd | Construction | 2017 |
| Rhdgs Limited | Information & communication | 2023 |
| Rhema Consult Ltd | Information & communication | 2016 |
| Rhiannon Properties Limited | Real estate | 1987 |
| Rhino Healthcare Limited | Financial services | 2023 |
| Rhizome Media Group Limited | Professional & scientific | 2004 |
| Rhodia Eco Services Limited | Professional & scientific | 1977 |
| Rhodia NO. 2 Limited | Professional & scientific | 1905 |
| Rhum Island Properties Limited | Real estate | 1999 |
| Rhydex Chemicals Limited | Wholesale & retail | 2022 |
| RI Consulting Ltd | Information & communication | 2025 |
| RI Engineering Works Ltd | Real estate | 2022 |
| RI FI Properties Limited | Financial services | 2023 |
| RI Gems Ltd | Transport & logistics | 2025 |
| RIA Property Group Ltd | Real estate | 2024 |
| Riaan Money Ltd | Financial services | 2015 |
| Riaan Travel and Tours Ltd | Administrative & support | 2025 |
| Riaan Travel Limited | Administrative & support | 2025 |
| Riaz Investment Group Ltd | Financial services | 2022 |
| Ribbon Factory Management Limited | Real estate | 2000 |
| Ricclo Limited | Extraterritorial | 2023 |
| Rice Bowl Watford Ltd | Hospitality | 2024 |
| Rice Bros (Ground Rents) Ltd | Real estate | 2009 |
| Rich Advice Limited | Information & communication | 2011 |
| Richant Limited | Wholesale & retail | 2023 |
| Richard Andrew Baxter Ltd | Professional & scientific | 2018 |
| Richard Hollis Limited | Information & communication | 2011 |
| Richard Malone Associates Limited | Professional & scientific | 2010 |
| Richard Messik Limited | Professional & scientific | 2013 |
| Richardson Projects (PVT) Limited | Administrative & support | 2000 |
| Richborough Energy Storage Limited | Energy | 2019 |
| Richborough Investments Limited | Real estate | 2022 |
| Richborough Ltd | Professional & scientific | 2019 |
| Richborough Technology Ltd | Information & communication | 2019 |
| Richmond Gate Investments Ltd | Real estate | 2026 |
| Richmond Management Company (ST Albans) Limited | Real estate | 2001 |
| Rickabin Rentals Limited | Real estate | 2011 |
| Ricky Road Guest House Limited | Hospitality | 2012 |
| Rickytech Industries Ltd | Construction | 2016 |
| Ricono Investment Limited | Other services | 2013 |
| Ride:Data Ltd | Professional & scientific | 2024 |
| Ridge Developments Limited | Construction | 1997 |
| Ridge Interiors Limited | Construction | 1982 |
| Ridge Residential Properties Limited | Real estate | 2014 |
| Ridgeway Court Residents Association Limited | Construction | 1979 |
| Ridgeway Gardens Management RTM Company Limited | Households | 2017 |
| Rifco Arts | Arts & recreation | 2002 |
| Rifco Productions Ltd | Arts & recreation | 2024 |
| Right 4 Recruitment Limited | Administrative & support | 2004 |
| Right Away Cleaning Right Away Removals Ltd | Transport & logistics | 2025 |
| Right Course Solutions Ltd | Financial services | 2014 |
| Right Prompt Technologies (UK) Limited | Information & communication | 2026 |
| Right Units Limited | Manufacturing | 1993 |
| Rightgas Group Limited | Manufacturing | 2017 |
| Rightnowclub Limited | Other services | 2025 |
| Rights Units Limited | Professional & scientific | 2000 |
| Rigorous Vision Limited | Professional & scientific | 2014 |
| Rika Biofuels Limited | Professional & scientific | 2010 |
| Rika Investments Limited | Real estate | 2017 |
| Rika Limited | Information & communication | 1994 |
| Rikani Ltd | Information & communication | 2020 |
| Riki Investment Limited | Real estate | 2020 |
| Rikkiconstruct Ltd | Construction | 2025 |