| Ready to Move Limited | Real estate | 2000 |
| Real Deal Radio Limited | Extraterritorial | 2026 |
| Real Estate Equities Ltd | Real estate | 1995 |
| Real Estate Housing Solutions Ltd | Real estate | 2026 |
| Real Perfect Climate Limited | Manufacturing | 2017 |
| Realcore Invest Limited | Real estate | 2025 |
| Realia Homes UK Limited | Real estate | 2020 |
| Realigned Online Ltd | Information & communication | 2026 |
| Really Smart Developments Limited | Real estate | 1997 |
| Realphd Limited | Education | 2025 |
| Realsmart Learning Ltd | Information & communication | 2004 |
| Reay Transport Ltd | Transport & logistics | 2024 |
| Rebecca Dickenson Hair Ltd | Other services | 2019 |
| Rebecca Dickenson Rentals Ltd | Other services | 2019 |
| Rebecca Parker Freelance Design Limited | Professional & scientific | 2017 |
| Rebel Art Class Limited | Education | 2024 |
| Rebel Curves Ltd | Wholesale & retail | 2025 |
| Rebel Grill Limited | Hospitality | 2026 |
| Rebel Rebel Music Ltd | Professional & scientific | 2024 |
| Rebirth Barber Ltd | Other services | 2020 |
| Rebooted Repair Solutions Ltd | Other services | 2026 |
| Recapture ME Ltd | Professional & scientific | 2023 |
| Recell Energy Anglesey Limited | Energy | 2022 |
| Recell Energy Ltd | Energy | 2018 |
| Recell Energy Projects Limited | Construction | 2022 |
| Reception Ltd | Extraterritorial | 2018 |
| Recert Training Solutions Ltd | Public administration | 2021 |
| Recharge Motion Ltd | Professional & scientific | 2021 |
| Recharge Service Tool Ltd | Wholesale & retail | 2026 |
| Recikels Limited | Wholesale & retail | 2023 |
| Recipe 4 Change Community Interest Company | Information & communication | 2025 |
| Reco Group Limited | Financial services | 2023 |
| Reco Turbo Limited | Manufacturing | 2010 |
| Recruitlea Ltd | Health & social care | 2024 |
| Rectified Electrical Ltd | Manufacturing | 2016 |
| Recycling 1ST Ltd | Water & waste | 2020 |
| Recyle CU Liujie Limited | Wholesale & retail | 2024 |
| Red and Co Properties (DN14) Limited | Real estate | 2025 |
| Red Barn Foods Ltd | Hospitality | 2026 |
| Red Beacon Ltd. | Professional & scientific | 2009 |
| Red Burger Ltd | Hospitality | 2024 |
| Red Circle Consultancy Limited | Professional & scientific | 2015 |
| Red Cortez Limited | Construction | 2021 |
| Red Eagle Revivals Limited | Administrative & support | 2023 |
| Red Hot Reaper Ltd | Manufacturing | 2022 |
| Red Lion Askern Ltd | Hospitality | 2020 |
| Red Medical Ltd | Health & social care | 2024 |
| Red Panda Movements Ltd | Administrative & support | 2026 |
| Red Peony Ltd | Hospitality | 2020 |
| Red Rose Medical Ltd | Health & social care | 2019 |
| Redbourne Cleaning Services Limited | Administrative & support | 2002 |
| Redbridge Craftworks Ltd | Extraterritorial | 2026 |
| Redbridge Logistics Group Ltd | Extraterritorial | 2026 |
| Redcrest Innovations Ltd | Extraterritorial | 2026 |
| Redd Property Management Limited | Real estate | 2024 |
| Redeemed Christian Church of GOD New Life Family Centre Doncaster | Education | 2025 |
| Redefined Fitness Ltd | Health & social care | 2025 |
| Redesign Ltd | Administrative & support | 2009 |
| Redfern Strategy Ltd | Wholesale & retail | 2025 |
| Redflow Services Limited | Professional & scientific | 1999 |
| Redline Assured Security Limited | Administrative & support | 2006 |
| Redline Diagnostics and Repairs (Doncaster) Limited | Wholesale & retail | 2026 |
| Redline Diagnostics and Repairs Ltd | Wholesale & retail | 2025 |
| Redmile ANP Ltd | Health & social care | 2019 |
| Redmileseal Maintenance Ltd | Construction | 2019 |
| Redpath Property Investment Ltd | Real estate | 2018 |
| Redroxservices Ltd | Construction | 2011 |
| Redscar Kitchens (Preston) Ltd | Manufacturing | 2018 |
| Redset Investments Ltd | Real estate | 2024 |
| Redshape Limited | Extraterritorial | 2012 |
| Redthorn Ventures Ltd | Extraterritorial | 2026 |
| Redvik Limited | Professional & scientific | 2011 |
| Redwhite Management LLP | | 2011 |
| Redwill Construction Limited | Construction | 2014 |
| Redwood & RYE Ltd | Extraterritorial | 2026 |
| Redwood Trees & Groundworks Limited | Administrative & support | 2024 |
| Reebex Limited | Real estate | 2003 |
| Reed Building Ltd | Construction | 2018 |
| Reed Estates Group Limited | Administrative & support | 2017 |
| Reed Group Holdings Ltd | Construction | 2020 |
| Reefstone Limited | Extraterritorial | 2013 |
| Reemsborko Limited | Professional & scientific | 2018 |
| Reeve & Brown Developments Ltd | Construction | 2017 |
| Reeve Investment Holdings Ltd | Financial services | 2018 |
| Refca Ltd | Professional & scientific | 2021 |
| Refinedgardens&Landscaping Ltd | Construction | 2026 |
| Refinishing Right Limited | Wholesale & retail | 2024 |
| Refinishing Services Ltd | Professional & scientific | 2018 |
| Reflo Sports Ltd | Manufacturing | 2021 |
| Refood Limited | Professional & scientific | 2008 |
| Refood UK Limited | Energy | 2008 |
| Reform Heating Limited | Construction | 2026 |
| Refractory Crucibles Limited | Administrative & support | 2007 |
| Refurb O'Clock Construction Ltd | Construction | 2026 |
| Refyne Wellness Ltd | Other services | 2026 |
| REG Broad UK Investment Ltd | Information & communication | 2025 |
| REG Directory Limited | Wholesale & retail | 2020 |
| Regal House Limited | Real estate | 2018 |
| Regal Tree Ltd | Hospitality | 2023 |
| Regalmark Limited | Wholesale & retail | 2012 |