| Reforme Medical Limited | Health & social care | 2022 |
| Reframed Land Ltd | Professional & scientific | 2022 |
| Refran FO Limited | Information & communication | 2025 |
| Refresh Airbnb Ltd | Real estate | 2024 |
| Refresh NOW Corporate Energy Limited | Wholesale & retail | 2014 |
| Refresh NOW Limited | Wholesale & retail | 2009 |
| Refresh Surplus Limited | Wholesale & retail | 2024 |
| Refreshing Consultancy Limited | Professional & scientific | 2025 |
| Refreshprices Ltd | Wholesale & retail | 2022 |
| Refrigeration and Shopfitting Services Limited | Construction | 2025 |
| Refson Engineering Design Ltd. | Manufacturing | 2014 |
| Refurb Plus Ltd | Construction | 2020 |
| Refurbit Hampshire Limited | Construction | 2019 |
| REG Construction Limited | Construction | 2016 |
| REG Rings Ltd | Wholesale & retail | 2021 |
| Regal Capital UK Ltd | Real estate | 2013 |
| Regal Magazines Limited | Information & communication | 2010 |
| Regal Pet Palace Ltd | Manufacturing | 2024 |
| Regal Tech Line Ltd | Information & communication | 2025 |
| REGALIS28 Ltd | Other services | 2025 |
| Regalo TS Ltd | Real estate | 2021 |
| Regaloak Capital Partners Limited | Wholesale & retail | 2025 |
| Regan Developments Ltd | Information & communication | 2019 |
| Regan Management Limited | Real estate | 2009 |
| Regan Neighbourhoods Limited | Real estate | 2025 |
| Regan Print & Display Ltd | Manufacturing | 2020 |
| Regan's Electrical Services Limited | Construction | 2014 |
| Regen Go TT Trade Co., Ltd | Extraterritorial | 2021 |
| Regenative Limited | Professional & scientific | 2018 |
| Regency Developments Ltd | Real estate | 2024 |
| Regency Marketing Ltd | Information & communication | 2018 |
| Regency Oils (Wales) Limited | Hospitality | 2014 |
| Regency Playworks Ltd | Information & communication | 2026 |
| Regency Waste Management Ltd | Water & waste | 2021 |
| Regency Wealth Investments Ltd | Financial services | 2021 |
| Regeneration Investment Fund for Wales LLP | | 2009 |
| Regenica Ltd | Health & social care | 2025 |
| Regensys IT Ltd | Wholesale & retail | 2019 |
| Regent Brickwork Ltd | Construction | 2026 |
| Regent Commercial Window Cleaning Limited | Administrative & support | 2017 |
| Regent Gardens (Cardiff) Management Company Limited | Hospitality | 2005 |
| Regent Gutter and Driveway Maintenance Limited | Administrative & support | 2022 |
| Regent Property Advisors Ltd | Real estate | 2025 |
| Regent Property Management Advisors Ltd | Households | 2025 |
| Regent Property Services Advisors Ltd | Construction | 2025 |
| Regent Strategy Ltd | Professional & scientific | 2016 |
| Regent Street Threads Limited | Wholesale & retail | 2026 |
| Regent Trading Limited | Wholesale & retail | 2019 |
| Regent Walls Ltd | Construction | 2018 |
| Regentcore Global Ltd | Wholesale & retail | 2025 |
| Regents Court (Cardiff) Management Limited | Real estate | 2001 |
| Regents Gate (Cardiff) RTM Company Limited | Households | 2022 |
| Reginald AI Ltd | Information & communication | 2025 |
| Reginald Atkin (Holdings) Limited | Construction | 1978 |
| Reginald Ford Limited | Wholesale & retail | 1933 |
| REGIOADS24 Ltd | Professional & scientific | 2021 |
| Region Reign Limited | Administrative & support | 2016 |
| Regionalreach Limited | Information & communication | 2025 |
| Regions Direct Limited | Real estate | 2021 |
| Regis Counselling Service Limited | Health & social care | 2016 |
| Regis Fuel Logistics Limited | Transport & logistics | 2002 |
| Regis Green Property Ltd | Real estate | 2020 |
| Registered Accountants Ltd | Extraterritorial | 2024 |
| Registered Auditors Limited | Professional & scientific | 2015 |
| Regitra Ltd | Professional & scientific | 2023 |
| Regius Inc Ltd | Information & communication | 2012 |
| Regmac Air Conditioning Ltd | Construction | 2023 |
| Regno Software Limited | Information & communication | 2018 |
| Rego Motors Ltd | Wholesale & retail | 2019 |
| Rego Sport and Exercise Medicine Services Ltd | Health & social care | 2014 |
| Regros International Ltd | Information & communication | 2019 |
| Regroup Sussex Limited | Construction | 2015 |
| Regs First Ltd | Public administration | 2019 |
| Regulatory Consulting Services Ltd | Professional & scientific | 2023 |
| REHAB24 Limited | Health & social care | 2012 |
| Rehbar Ltd | Wholesale & retail | 2025 |
| Reheem Ltd | Financial services | 2014 |
| Rehoboth and Manny Ltd | Professional & scientific | 2019 |
| Rehoboth Care & Wellness Limited | Administrative & support | 2026 |
| Rehoboth Consulting Engineers Ltd | Professional & scientific | 2018 |
| Rehoboth Partners Ltd | Information & communication | 2018 |
| Reid & Sons (Property) Limited | Real estate | 2016 |
| Reid Building Limited | Construction | 2020 |
| Reign Collective Group Ltd | Professional & scientific | 2019 |
| Reign Enterprise Ltd | Wholesale & retail | 2019 |
| Reign Financial Services Ltd | Financial services | 2020 |
| REIGNEL9 Ltd | Transport & logistics | 2025 |
| Reignited Ltd | Other services | 2026 |
| Reignscreen Installations Limited | Construction | 2018 |
| Reimagine Content Marketing Ltd | Professional & scientific | 2020 |
| Reimagine NOW Ltd | Professional & scientific | 2024 |
| Reinass Hair Limited | Wholesale & retail | 2019 |
| Reindeer Court Development Corporation Limited | Real estate | 2016 |
| Reine Chic Ltd | Wholesale & retail | 2025 |
| Reinspire Properties Ltd | Real estate | 2020 |
| Reinventy Ltd | Professional & scientific | 2023 |
| Reinvigoration Group Limited | Administrative & support | 2023 |
| Reinvigoration Group Services Limited | Administrative & support | 2024 |
| Reinvigoration Ltd | Professional & scientific | 2008 |
| Reirei Ltd. | Arts & recreation | 2026 |