| Realise Futures CIC | Hospitality | 2011 |
| Realscene Software Consultancy Limited | Information & communication | 1992 |
| Rebel Holdings Ltd | Real estate | 2024 |
| Rebellion Ventures Limited | Construction | 2023 |
| Rebirt Limited | Wholesale & retail | 2019 |
| Reboot Education Limited | Education | 2023 |
| Rebstone Strategies Ltd | Administrative & support | 2015 |
| Recast Property Group Limited | Construction | 2020 |
| Recharge + Repeat Ltd | Extraterritorial | 2025 |
| Recoupler Limited | Information & communication | 2021 |
| Recruiter Group Limited | Administrative & support | 2024 |
| Recruitment 46 Ltd | Administrative & support | 2024 |
| Recruitment Education Global Ltd | Administrative & support | 2026 |
| Rectory Farm Barns (Henley) Management Company Limited | Households | 2006 |
| Rectory Garden Montessori School Ltd | Education | 2019 |
| Red 5 Property Limited | Construction | 2012 |
| Red Brique Ltd | Real estate | 2016 |
| Red Cactus Media Ltd. | Information & communication | 2014 |
| Red COW Contracting Ltd | Agriculture & fishing | 2025 |
| Red DOT Europe Ltd | Manufacturing | 1998 |
| Red Dragon Line Limited | Transport & logistics | 2003 |
| Red Flag Awareness CIC | Education | 2025 |
| Red Flag Awareness Consultancy Ltd | Education | 2025 |
| Red Flame Communications Ltd | Professional & scientific | 2019 |
| Red Hall Court Management Company Limited | Households | 1999 |
| Red Lion Bramford Road Ltd | Hospitality | 2026 |
| Red Moon Productions Ltd | Information & communication | 1997 |
| Red Oak Taverns Acquisitions Limited | Hospitality | 2015 |
| Red Oak Taverns Finance Limited | Administrative & support | 2011 |
| Red Oak Taverns Group Holdings Limited | Professional & scientific | 2015 |
| Red Oak Taverns Group Topco Limited | Financial services | 2022 |
| Red Oak Taverns Holdings Limited | Professional & scientific | 2011 |
| Red Oak Taverns Intermediary Limited | Administrative & support | 2015 |
| Red Oak Taverns Limited | Hospitality | 2011 |
| Red Robin Medical Limited | Health & social care | 2018 |
| Red Rocket Web Design Ltd | Other services | 2017 |
| Red Rose Chain | Arts & recreation | 1999 |
| Red Snack Shop Ltd | Wholesale & retail | 2026 |
| Red Squirrel Investing Ltd | Real estate | 2025 |
| Red Willow Construction Ltd | Administrative & support | 2017 |
| Redbourne Homes (Beyton) Limited | Construction | 2023 |
| Redbourne Homes (Creeting) Limited | Construction | 2019 |
| Redbourne Homes (Epworth) Limited | Construction | 2009 |
| Redbourne Homes (Kettleburgh) Limited | Construction | 2023 |
| Redbourne Homes (Warboys) Limited | Construction | 2008 |
| Redbourne Homes Limited | Construction | 2009 |
| Redbourne XYZ Limited | Construction | 2010 |
| Redech Ltd | Wholesale & retail | 2021 |
| Redeye Records (Holdings) Limited | Wholesale & retail | 2019 |
| Redeye Records Limited | Wholesale & retail | 2005 |
| Redford (Kent) Limited | Construction | 2015 |
| Redhill Farms (Shotley) Limited | Agriculture & fishing | 2012 |
| Redlands Property Group Limited | Real estate | 2021 |
| Redmon Energy Ltd | Other services | 2022 |
| Reds Scaffolding Ltd | Construction | 2008 |
| Redstart Property Developments Limited | Construction | 2017 |
| Redstart Property Limited | Real estate | 2016 |
| Redstart Serviced Accommodation Limited | Real estate | 2018 |
| Redwald Estates Limited | Real estate | 2016 |
| Redwood Carpentry (East Anglia) Limited | Construction | 2012 |
| REE Trading Limited | Wholesale & retail | 2025 |
| Reed Digital Ltd | Manufacturing | 2006 |
| Reed Motorsport Ltd | Arts & recreation | 2024 |
| Reeda Ltd | Administrative & support | 2010 |
| Reedpalm Limited | Construction | 2020 |
| Reef GRO Limited | Agriculture & fishing | 2026 |
| Reelon Media Limited | Information & communication | 2025 |
| Reena Waterday Ltd | Arts & recreation | 2023 |
| Reeves Events Limited | Hospitality | 2023 |
| Refine Aesthetics Clinic Ltd | Other services | 2026 |
| Refined Cedar Ltd | Wholesale & retail | 2025 |
| Reforge Martial Arts Ltd | Education | 2025 |
| Reformer Works 4 U Limited | Health & social care | 2015 |
| Refresh Wellness Limited | Arts & recreation | 2016 |
| REG Helping Citizens Centre Ltd | Professional & scientific | 2024 |
| Regain GAS and Heating Services Limited | Professional & scientific | 2024 |
| Regency Access Ltd | Health & social care | 2024 |
| Regency Court Management Company (Ipswich) Limited | Real estate | 1998 |
| Regency Events & Corporate Services Limited | Administrative & support | 2023 |
| Regency Property Management (Suffolk) Limited | Households | 2023 |
| Regeneration Homes Limited | Real estate | 2025 |
| Regenerative Foods Ltd | Hospitality | 2025 |
| Regent Publicity (2020) Ltd | Wholesale & retail | 2019 |
| Regent Publicity Limited | Wholesale & retail | 1982 |
| Regift IT Ltd | Information & communication | 2025 |
| Regional Clearance Ltd | Water & waste | 2026 |
| Rehmark Enterprises Ltd | Wholesale & retail | 2025 |
| Rehoboth Property Developers Limited | Construction | 2020 |
| Rehoboth Sanctuary Ltd | Construction | 2025 |
| Rehr Ltd | Real estate | 2026 |
| Reid Carpentry Limited | Construction | 2015 |
| Reja Holdings Ltd | Financial services | 2020 |
| Reju Wellness Limited | Other services | 2025 |
| Reju YOU Ltd | Manufacturing | 2025 |
| REL Property Limited | Real estate | 2018 |
| Relax Furniture Ltd | Wholesale & retail | 1953 |
| Relent Services Ltd | Administrative & support | 2023 |
| Reliable PAT Testing Limited | Manufacturing | 2017 |
| Reliaco Vehicle Components Limited | Wholesale & retail | 2013 |
| Reliontax Interaction Limited | Information & communication | 2026 |