| Ross House (Management) Company Limited | Households | 1984 |
| Ross House Freehold Management Company Limited | Households | 2003 |
| Ross Nursing Care Services Ltd | Health & social care | 2022 |
| Rossfield Design Limited | Administrative & support | 2009 |
| Rosslyn Close (Sunbury) Property Management Company Limited | Households | 1992 |
| Roswell View Management Company Limited | Real estate | 1994 |
| Rosyground Stud LLP | | 2019 |
| Rotana Cafe Cambridge Ltd. | Hospitality | 2013 |
| Roth&Chanet(Uk)Investment Group. Ltd. | Manufacturing | 2022 |
| Rotife Energy Limited | Professional & scientific | 2026 |
| Roto Enterprise Limited | Administrative & support | 2016 |
| Rotors Engineering Ltd | Manufacturing | 2023 |
| Roudan Ltd | Real estate | 2023 |
| Rough Timba Ltd | Wholesale & retail | 2026 |
| Roughacre Retail Limited | Wholesale & retail | 2023 |
| Round PEG Cambridge Ltd | Professional & scientific | 2016 |
| Round PEG Properties Ltd | Real estate | 1995 |
| Round Window Property Ltd | Real estate | 2017 |
| Round Wood Distillery Ltd | Manufacturing | 2016 |
| Round World Films Ltd | Information & communication | 2020 |
| Rourkus Consulting Ltd. | Information & communication | 2022 |
| Rouskas Engineering Ltd | Manufacturing | 2026 |
| Rowan Moore Ltd | Health & social care | 2023 |
| Rowan's Landscaping Ltd | Administrative & support | 2025 |
| Rowley Lane (Wexham) Limited | Construction | 2021 |
| Rowley Lane (Wexham) Management Company Limited | Construction | 2025 |
| Rowley Summit Limited | Real estate | 2025 |
| Rowlinson Cambridge Limited | Construction | 2020 |
| Rownhams Promotions Ltd | Real estate | 2014 |
| ROY Fleetwood Limited | Professional & scientific | 1985 |
| ROY Racing Ltd | Agriculture & fishing | 2015 |
| Roya Mideast Ltd | Wholesale & retail | 2024 |
| Royaal Spice Indian Takeaway Limited | Hospitality | 2020 |
| Royce Block Management Company Limited | Households | 2016 |
| Royce Mechanical Peterborough Limited | Construction | 2016 |
| Roydon Court Management Company Limited | Households | 1982 |
| Royginnah Care Services Ltd | Administrative & support | 2025 |
| Royston Media Ltd | Administrative & support | 2026 |
| Royston Park Fitness Limited | Arts & recreation | 2024 |
| ROZ Limited | Extraterritorial | 2017 |
| RP Biologics Ltd | Administrative & support | 2023 |
| RP Fitness Limited | Arts & recreation | 2015 |
| RP Giles Ltd | Real estate | 2019 |
| RP Inspections Ltd | Manufacturing | 2025 |
| RPM CAN Ltd | Construction | 2025 |
| Rpmarian Ltd | Manufacturing | 2023 |
| Rpna Ltd | Professional & scientific | 2022 |
| RR Brands (UK) Group Ltd. | Extraterritorial | 2024 |
| RR Estate Holdings Limited | Real estate | 2024 |
| Rrif Ltd | Financial services | 2010 |
| Rrmc Ltd | Construction | 2026 |
| Rrpj Limited | Hospitality | 2017 |
| RS Glazing Limited | Construction | 2022 |
| RS Merchants Ltd | Wholesale & retail | 2025 |
| RS Smart Electrical Ltd | Construction | 2026 |
| RS3D Design Ltd | Professional & scientific | 2019 |
| RSA Examinations Board | Education | 1993 |
| Rsaeb Pension Trust Company Limited | Administrative & support | 2011 |
| Rsarm Ltd | Other services | 2021 |
| RSB Landmark Ltd | Real estate | 2017 |
| Rsgct Corporate Trustee | Other services | 2026 |
| Rsgd Ventures Limited | Real estate | 2024 |
| RSM IT Consultancy Services Ltd | Information & communication | 2024 |
| RSN Trade Ltd | Wholesale & retail | 2025 |
| Rspamd Ltd | Information & communication | 2016 |
| RSR & P Limited | Real estate | 2015 |
| RSR Building Ltd | Construction | 2019 |
| RSR Lettings Ltd | Real estate | 2020 |
| Rsr&P Properties Limited | Real estate | 2024 |
| RT Surgical Limited | Health & social care | 2013 |
| RT Taxis Ltd | Transport & logistics | 2024 |
| RT Vehicle Solutions Limited | Wholesale & retail | 2025 |
| RT-MACHINING2025 Ltd | Manufacturing | 2025 |
| RTD Engineering Services Limited | Professional & scientific | 2026 |
| RTH Lettings Ltd. | Real estate | 2010 |
| RTJ Property Management Ltd | Real estate | 2025 |
| RTL Management Ltd | Extraterritorial | 2022 |
| Rtm-Digital-Services Ltd | Wholesale & retail | 2021 |
| RTW Consulting Services Ltd | Professional & scientific | 2016 |
| Rubicon Knights Park Management Company Limited | Households | 2021 |
| Rubinsztein Consulting Ltd | Professional & scientific | 2024 |
| Rubixco Ltd | Financial services | 2025 |
| Rubric Grid Ltd | Education | 2025 |
| Rubyfx Global Limited | Financial services | 2025 |
| Rubys (Abington) Limited | Wholesale & retail | 2025 |
| Rubys Restaurant Ltd | Hospitality | 2022 |
| Rubys Room (Abington) Limited | Wholesale & retail | 2024 |
| Rudding Holdings Limited | Financial services | 2021 |
| Rudham Safety and Environmental Ltd. | Professional & scientific | 2016 |
| Rudston Products (INT) Limited | Manufacturing | 1969 |
| Ruff Productions Ltd. | Information & communication | 2014 |
| Rufford Pastures Estates Limited | Households | 2018 |
| Ruflo Construction and Landscaping Limited | Construction | 2017 |
| Ruiheng International Trading Limited | Extraterritorial | 2016 |
| Ruishen Co., Ltd | Transport & logistics | 2021 |
| Ruixin International Trade Limited | Extraterritorial | 2017 |
| Ruiyitong E-Commerce Co., Limited | Wholesale & retail | 2023 |
| Ruiz Gomez Aeronautic Ltd | Manufacturing | 2026 |
| Rumbles Fish Ltd | Hospitality | 2022 |
| Rumfitt Associates Limited | Professional & scientific | 2025 |