| RAY IT Consulting Services Limited | Information & communication | 2005 |
| Raymond Bell Associates LLP | | 2005 |
| RBH Programme Partners Ltd | Information & communication | 2025 |
| RCG Motors Ltd | Wholesale & retail | 2024 |
| RDT Design Limited | Real estate | 2005 |
| Reading Accident Repairs Limited | Wholesale & retail | 2003 |
| Realife Properties Limited | Extraterritorial | 2016 |
| Realmpark Health Care (Petworth) Limited | Health & social care | 1996 |
| Reatech Dental Services Limited | Other services | 2002 |
| Red Decorators Limited | Construction | 2005 |
| Red Door Recruitment Limited | Administrative & support | 2006 |
| Red Road Management Limited | Real estate | 1983 |
| Redbourn Recreation Centre and Playing Fields Trust | Arts & recreation | 1995 |
| Redfoot Design Limited | Professional & scientific | 1998 |
| Reefbloomornaments Ltd | Wholesale & retail | 2025 |
| Rees Flooring Limited | Construction | 1982 |
| Refined Estates Limited | Professional & scientific | 2001 |
| Refined Holdings Limited | Professional & scientific | 2004 |
| Refrose Properties Limited | Real estate | 1986 |
| Regal Bedrooms Limited | Construction | 2002 |
| Regal Property Holdings Ltd | Real estate | 2025 |
| Regent Estates Property Limited | Real estate | 2002 |
| Regulatory Support Limited | Health & social care | 1998 |
| Rekap Limited | Health & social care | 2007 |
| Rekap Property Ltd | Real estate | 2024 |
| Relatewater Limited | Real estate | 2003 |
| Reload Group Ltd | Financial services | 2023 |
| Remzi Properties Ltd | Real estate | 2021 |
| Replikit Limited | Wholesale & retail | 2005 |
| Request Limited | Other services | 2006 |
| Research First Limited | Professional & scientific | 1997 |
| Resicare Homes Limited | Health & social care | 1995 |
| Result Holdings Limited | Administrative & support | 2004 |
| Retina 888 | Administrative & support | 2013 |
| Retro Properties Limited | Real estate | 2004 |
| Revolution Paint Repairs Ltd | Administrative & support | 2016 |
| Reyhold Limited | Professional & scientific | 2015 |
| Rich N Radianz PVT Ltd | Wholesale & retail | 2023 |
| Richbear Limited | Wholesale & retail | 2026 |
| Richmond Financial Services Limited | Financial services | 1999 |
| Ricky Williams Limited | Manufacturing | 2003 |
| Ride 2 UK Limited | Transport & logistics | 2025 |
| Rising Sun (MCD) Limited | Hospitality | 2017 |
| Risk Audit Professional Development Limited | Information & communication | 1999 |
| Risk Audit Recruitment Services Limited | Administrative & support | 2000 |
| Risk DNA Limited | Professional & scientific | 2002 |
| Riskscape Law Ltd | Information & communication | 1999 |
| Ritz Hygiene Limited | Health & social care | 2005 |
| Rivendell Solutions Ltd | Information & communication | 2007 |
| Riverbanks Estate Management (Harpenden) Limited | Administrative & support | 1997 |
| Riverside Nannies and Mothers' Help Limited | Administrative & support | 1994 |
| RJK Electrical Services Ltd | Construction | 2023 |
| Rmbs Ltd. | Administrative & support | 1997 |
| RO 104 Limited | Manufacturing | 2023 |
| RO Developments Limited | Construction | 2001 |
| RO Group Limited | Professional & scientific | 2002 |
| Roadfern Ltd | Construction | 2003 |
| Roadside Group Ltd | Wholesale & retail | 1995 |
| ROB Yeldham Associates Limited | Information & communication | 2001 |
| Robarb Searches Limited | Construction | 2003 |
| Robert Francis Holdings Limited | Extraterritorial | 2006 |
| Robert P.D. Frost & Co. Limited | Manufacturing | 1998 |
| Roberto & Co Property Solutions Ltd | Real estate | 2025 |
| Roberts & Co (Accountants) Ltd | Professional & scientific | 2002 |
| Roberts & Co Limited | Professional & scientific | 2004 |
| Robex Contracting Limited | Construction | 2003 |
| Robin Kuzey Ltd | Wholesale & retail | 2023 |
| Robinglade Limited | Extraterritorial | 1994 |
| Robinson Family Butchers Limited | Wholesale & retail | 2005 |
| ROC Hair & Beauty Limited | Other services | 2004 |
| Rocha Suit Limited | Other services | 2012 |
| Roche Holding (UK) Limited | Professional & scientific | 1997 |
| Roche Products Pension Trust Limited | Professional & scientific | 1950 |
| Rockit Limited | Information & communication | 1998 |
| Rockley Sands (Estates) Limited | Hospitality | 1956 |
| Rockstar Software Ltd | Extraterritorial | 1998 |
| Rockways BIO Ltd | Professional & scientific | 2025 |
| ROE LEE Gardens Management Company Limited | Households | 2018 |
| Ronsek Limited | Professional & scientific | 2004 |
| Room-By-Room (UK) Ltd | Professional & scientific | 1999 |
| Rooms Refreshed Limited | Construction | 2003 |
| Rosam Assets LLP | | 2020 |
| Rosebery Court Residents Association (Harpenden) Limited | Households | 1968 |
| Rosehill Court Management Limited | Households | 1986 |
| Rosie Mcclelland Global Ltd | Real estate | 2021 |
| Rosina Cafe Ltd | Hospitality | 2023 |
| Ross Bennett Limited | Arts & recreation | 2006 |
| Ross Cottenden Preservations Limited | Construction | 2006 |
| Ross Plumbing Limited | Construction | 2007 |
| Rowley Park Management Limited | Real estate | 1981 |
| Rowleys: London Limited | Professional & scientific | 2001 |
| Royde & Tucker Holdings Limited | Professional & scientific | 2003 |
| Royde & Tucker Limited | Manufacturing | 1954 |
| RP Projects Limited | Professional & scientific | 2007 |
| RPM Real Estate Ltd | Real estate | 2025 |
| RS Design Solutions Ltd | Professional & scientific | 2018 |
| Rubi Foods Ltd | Hospitality | 2024 |
| Rubu Online Ltd | Wholesale & retail | 2023 |
| Rudra Tech-Uk Ltd | Information & communication | 2021 |
| Rufus Design Limited | Information & communication | 2007 |