| Regal Gildedloft Limited | Information & communication | 2024 |
| Regal Simms Ltd | Real estate | 2024 |
| Regal Units Ltd | Real estate | 2025 |
| Regalbury Limited | Other services | 2021 |
| Regarding Ltd | Information & communication | 2023 |
| Regency Crescent RTM Company Limited | Households | 2011 |
| Regency Electrics Bromley Ltd | Construction | 2014 |
| Regenerate Wellness Ltd | Other services | 2025 |
| Regent 77 Ltd | Financial services | 2022 |
| Regent Blend Limited | Wholesale & retail | 2022 |
| Regentiv Specialist Skincare Ltd | Other services | 2024 |
| Regents Court ST Albans Freehold (Rcsaf) Limited | Real estate | 2013 |
| Regina Margarita Pizzeria Ltd | Hospitality | 2024 |
| Regina Wealth Ltd | Real estate | 2025 |
| Regional Pest Services Ltd | Administrative & support | 2020 |
| Reglaze My Glasses Ltd | Wholesale & retail | 2015 |
| Regser Limited | Professional & scientific | 2024 |
| Regysartistry Ltd | Other services | 2026 |
| Rehab Walk Limited | Professional & scientific | 2008 |
| Rehoboth Accountants Ltd. | Professional & scientific | 2015 |
| Reids Real Estate Ltd | Real estate | 2024 |
| Reilly Civil Engineering Equipment Limited | Administrative & support | 2024 |
| Reilly Surfacing Limited | Construction | 2021 |
| Rein Pain Limited | Administrative & support | 2013 |
| Rejesha Healthcare Limited | Health & social care | 2022 |
| Rejuvenade Limited | Health & social care | 2023 |
| Rekhoboth Holdings Ltd | Real estate | 2023 |
| REL Developments Limited | Administrative & support | 2014 |
| REL Land Development Limited | Construction | 2019 |
| Relab Solutions Limited | Wholesale & retail | 2025 |
| Relay Direct Limited | Administrative & support | 2022 |
| Relco Solutions Limited | Manufacturing | 2022 |
| Relco UK Limited | Manufacturing | 1998 |
| Relentless Trading Limited | Construction | 2010 |
| Reliance Resourcing Ltd | Administrative & support | 2014 |
| Reliant Machinery Limited | Manufacturing | 2001 |
| Rell Consult Ltd. | Wholesale & retail | 2007 |
| REM Fabricate London Limited | Arts & recreation | 2017 |
| Remade With Hope Limited | Manufacturing | 2016 |
| Remaglow Marketing Limited | Information & communication | 2022 |
| Remark AI UK Limited | Information & communication | 2019 |
| Remarkable Thinking Ltd | Information & communication | 2021 |
| Rembrandt House RTM Company Limited | Households | 2022 |
| Remerge Services Ltd | Administrative & support | 2022 |
| Renable Research Ltd | Professional & scientific | 2019 |
| Renaissance by Sara Limited | Wholesale & retail | 2015 |
| Renaissance Cars Ltd | Wholesale & retail | 2024 |
| Renasense Homeware Limited | Information & communication | 2017 |
| Renaura Wellness Ltd | Hospitality | 2023 |
| Rendips Limited | Professional & scientific | 2023 |
| Renewable Energy Distribution Limited | Professional & scientific | 2011 |
| Renewable Energy Heatworks Ltd | Construction | 2025 |
| Renewell Ltd | Health & social care | 2008 |
| Rennie & Co Limited | Real estate | 2001 |
| Rennie and Co. (Croxley) Limited | Real estate | 2008 |
| Rennie Grove Peace Hospice Care | Health & social care | 2022 |
| Renoval Construct Ltd | Construction | 2022 |
| Renovare Haus Ltd | Construction | 2025 |
| Rent Result Ltd | Professional & scientific | 2016 |
| Rent-A-Budo Ltd | Wholesale & retail | 2025 |
| Rental-Home Property Investments Limited | Real estate | 2025 |
| Renuka IT Solutions Limited | Information & communication | 2010 |
| Reosoft Limited | Information & communication | 2017 |
| REP BI Ltd | Professional & scientific | 2015 |
| Repair Daemon Limited | Other services | 2017 |
| Repairable LDN Ltd | Construction | 2025 |
| Replete Consulting Ltd | Professional & scientific | 2018 |
| Reply Intelligence Group Ltd | Information & communication | 2026 |
| Repossession Rescue Ltd | Professional & scientific | 2018 |
| Republic of Hifi Ltd | Wholesale & retail | 2022 |
| Requestflow Ltd | Information & communication | 2026 |
| Requinte Brazil Meat Market Ltd | Wholesale & retail | 2022 |
| Requisite Accounting Limited | Professional & scientific | 2025 |
| Resalcal Ltd | Information & communication | 2024 |
| Resell Academy Limited | Information & communication | 2023 |
| Resho Ltd | Hospitality | 2013 |
| Residential Nest Limited | Real estate | 2025 |
| Residential Progression Ltd | Administrative & support | 2026 |
| Residents Management (NO. 18) Limited | Real estate | 1985 |
| Resincare Limited | Construction | 1994 |
| Resintek Limited | Construction | 2008 |
| Resintek Services Limited | Construction | 1993 |
| Resolve Legal Services Ltd | Professional & scientific | 2025 |
| Resonance Pictures Ltd | Arts & recreation | 2025 |
| Resource ALL Ltd | Real estate | 2017 |
| Resourcewise Consultancy Ltd | Information & communication | 2019 |
| Resparkle Smiles Limited | Health & social care | 2022 |
| Respira Diagnostics Ltd | Wholesale & retail | 2026 |
| Restart Websites Ltd | Information & communication | 2023 |
| Restaurant Hub Limited | Information & communication | 2021 |
| Restorative NOW Limited | Health & social care | 2014 |
| Resydent Ltd | Real estate | 2021 |
| Retail Advertising Ltd | Professional & scientific | 2009 |
| Retail Digital Media Ltd | Professional & scientific | 2011 |
| Retail Park and Shopping Centre Media Limited | Professional & scientific | 2014 |
| Retailsolutions AG (UK) Limited | Information & communication | 2015 |
| Rethinking Outsourcing Limited | Professional & scientific | 2013 |
| Reticence Ltd | Extraterritorial | 2019 |
| Reto Building Consultancy Limited | Construction | 2024 |
| Retro Hifi Ltd | Extraterritorial | 2014 |