| Redbarn Properties Limited | Real estate | 2003 |
| Redbite Solutions Ltd | Professional & scientific | 2006 |
| Redbrick Property Development and Management Service Limited | Real estate | 2016 |
| Redcroft Investments Limited | Real estate | 2016 |
| Reddy Retail Ltd | Wholesale & retail | 2021 |
| Reddy's 2 Ltd | Wholesale & retail | 2017 |
| Redeye Technologies Limited | Information & communication | 2023 |
| Redfan Solutions Limited | Professional & scientific | 2024 |
| Redhue Limited | Extraterritorial | 2009 |
| Redlake Investments Limited | Financial services | 2021 |
| Redlehmbr Engineering Services Limited | Wholesale & retail | 2018 |
| Redmayne Miller Rees Limited | Real estate | 2002 |
| Redone Football Investment Group Ltd | Professional & scientific | 2023 |
| Redroc Properties Limited | Construction | 2020 |
| Redrose Ventures Ltd | Hospitality | 2024 |
| Redswift Ltd. | Information & communication | 2008 |
| Redtech Recruitment Ltd | Administrative & support | 2019 |
| Redventure Marketing & Communications Ltd | Professional & scientific | 2018 |
| Redwin Holdings Limited | Agriculture & fishing | 1985 |
| Redwood Integrity Group Ltd | Administrative & support | 2024 |
| Reel Tense Ltd | Information & communication | 2023 |
| Reela RAE Limited | Health & social care | 2022 |
| Reem Assil Ltd | Professional & scientific | 2023 |
| Reepham Renewables Limited | Energy | 2024 |
| Reesp Europe Ltd | Manufacturing | 2024 |
| Reeve Photography Limited | Professional & scientific | 2009 |
| Reeves Construction Limited | Construction | 2023 |
| Reeves Maehler Ltd | Administrative & support | 2025 |
| Reface Solutions Ltd | Construction | 2018 |
| Refined Trading Company Limited | Extraterritorial | 2023 |
| Refit and Refine Ltd | Wholesale & retail | 2024 |
| Reflecta Consulting Limited | Professional & scientific | 2014 |
| Reflectionwave Co., Limited | Information & communication | 2024 |
| Reforest Trading Limited | Agriculture & fishing | 2019 |
| Reform Property Solutions Ltd | Wholesale & retail | 2023 |
| Refresh Gardens Ltd | Administrative & support | 2023 |
| Refri-Gas Solutions Limited | Manufacturing | 2026 |
| Regal Tool Hire Ltd | Manufacturing | 2014 |
| Regalstar Catering Limited | Hospitality | 1999 |
| Regatta Bidco Limited | Financial services | 2019 |
| Regatta Holdco Limited | Financial services | 2019 |
| Regatta Midco Limited | Financial services | 2019 |
| Regatta Topco Limited | Financial services | 2019 |
| Regdd Limited | Information & communication | 2022 |
| Regency Aerials (Cambridge) Limited | Information & communication | 1990 |
| Regency Autos Limited | Manufacturing | 2007 |
| Regency Heating and Plumbing Services Ltd | Construction | 2022 |
| Regency House Publishing Limited | Information & communication | 1991 |
| REGENER8 Property Solutions Ltd | Construction | 2026 |
| Regent by Citystay Limited | Hospitality | 2021 |
| Regent Construction(Cambridge) Limited | Administrative & support | 2008 |
| Regent Court (Caversham) Residents Association Limited | Households | 1986 |
| Regent Court (Willingham) Limited | Households | 1974 |
| Regina Business Limited | Extraterritorial | 2014 |
| Reginald Ltd | Wholesale & retail | 2024 |
| Regional Economic Alliance Limited | Administrative & support | 2018 |
| Regnum Anglia Ltd | Construction | 2026 |
| Regolo Limited | Professional & scientific | 2025 |
| Regulatory Genome Development Ltd | Information & communication | 2020 |
| Regulogix Consulting Ltd | Professional & scientific | 2024 |
| Regulus Global Limited | Wholesale & retail | 2023 |
| Rehab Care Ltd | Health & social care | 2024 |
| Reideate Ltd | Information & communication | 2020 |
| Reidio Ltd | Information & communication | 2025 |
| Rejen Developments Ltd | Construction | 2021 |
| Rejuvenation Trading Limited | Wholesale & retail | 2024 |
| Reka Industries Co., Ltd | Professional & scientific | 2020 |
| Relational AI LAB Ltd | Information & communication | 2026 |
| Relational Consultants Limited | Information & communication | 1989 |
| Relational Peacebuilding Initiatives (UK) Ltd | Professional & scientific | 2019 |
| Relational Research Limited | Administrative & support | 2009 |
| Relaunch IT Ltd | Wholesale & retail | 2019 |
| Relevant Cafe & Bar Ltd | Hospitality | 2024 |
| Relevant Cocktail Limited | Hospitality | 2025 |
| Relevant Dog's Limited | Other services | 2026 |
| Relevant Opera Limited | Education | 2024 |
| Relevant Records Limited | Wholesale & retail | 2013 |
| Reliance Care Services Limited | Health & social care | 2017 |
| Reliance Force Limited | Wholesale & retail | 2023 |
| Reliance Group Holdings Limited | Wholesale & retail | 2023 |
| Relic Recycle Ltd | Wholesale & retail | 2024 |
| Rellor Ltd | Wholesale & retail | 2022 |
| Relyonus Plumbing and Heating Limited | Construction | 2022 |
| REM Arts Ltd | Wholesale & retail | 2017 |
| REM Compliance Services Limited | Professional & scientific | 2013 |
| Remane Limited | Administrative & support | 1980 |
| Remediation Technologies Ltd | Water & waste | 2010 |
| Remedium Energy Ltd | Energy | 2023 |
| Remostart Limited | Information & communication | 2024 |
| Remtec Talent Management Ltd | Administrative & support | 1998 |
| Remus Badea Avionics Ltd | Manufacturing | 2025 |
| Remus SRL Ltd | Manufacturing | 2025 |
| Remy Advisory Limited | Administrative & support | 2017 |
| Renaissance 2 (Cambridge) Management Company Limited | Households | 2009 |
| Renate International Mining (Russia) Group Co., Ltd | Wholesale & retail | 2023 |
| Rendchris Limited | Health & social care | 2015 |
| Rengoku Limited | Professional & scientific | 2022 |
| Renke Trading Co., Ltd | Wholesale & retail | 2023 |
| Renlee Limited | Information & communication | 2023 |
| Rennet & Rind Limited | Extraterritorial | 2022 |