| Readylec Limited | Construction | 2017 |
| Real Estate Strategies Limited | Real estate | 2013 |
| Real Lean Consulting Limited | Professional & scientific | 2024 |
| Real Procurement Solutions Limited | Professional & scientific | 2023 |
| Real Wood OR Knot Ltd | Construction | 2018 |
| Real World Evidence Ltd | Professional & scientific | 2025 |
| Real Wzrd Ltd | Information & communication | 2024 |
| Reality Events Ltd | Hospitality | 2024 |
| Really Excellent Advertising Limited | Professional & scientific | 2002 |
| Really Great Places to Stay Limited | Hospitality | 2022 |
| Realoneldn Ltd | Transport & logistics | 2023 |
| Ream-Uk Ltd | Health & social care | 2019 |
| Reaprs Ltd | Manufacturing | 2026 |
| Reavey & SON LLP | | 2012 |
| Rebamz Global Limited | Health & social care | 2025 |
| Rebar Kebabs Limited | Extraterritorial | 2019 |
| Rebecca Gordon Art Advisory Limited | Arts & recreation | 2021 |
| Rebecca H Salons Limited | Other services | 2013 |
| Rebecca Rogerson Ltd | Education | 2020 |
| Rebecca Warrant Aesthetics Ltd | Health & social care | 2021 |
| Rebel Male Grooming and Styling Ltd | Other services | 2021 |
| Reborn Games LLP | | 2026 |
| Rebound Consulting Ltd | Construction | 2026 |
| Recipe Design Limited | Professional & scientific | 2020 |
| Recline Property Ltd | Real estate | 2022 |
| Recliner Medic Ltd | Other services | 2023 |
| Recliner Parts UK Ltd | Wholesale & retail | 2025 |
| Record Management Limited | Professional & scientific | 1999 |
| Recovery & Wellness Property Services CIC | Real estate | 2024 |
| Recruitment Goals Ltd | Administrative & support | 2019 |
| Recycle IT (SW) Limited | Water & waste | 2024 |
| Recycled Ropes Ltd | Manufacturing | 2023 |
| Red Acorn Recruitment Limited | Administrative & support | 2007 |
| Red Admiral Contractors Limited | Administrative & support | 2023 |
| Red Admiral Vineyard Limited | Agriculture & fishing | 2019 |
| Red Alert Records Ltd | Wholesale & retail | 2023 |
| Red Box Tools Limited | Wholesale & retail | 2016 |
| Red Carpet Direct Limited | Administrative & support | 2018 |
| Red Dog Research Ltd | Professional & scientific | 2018 |
| Red Five Services Limited | Administrative & support | 2017 |
| Red Forest Fitness Ltd | Other services | 2012 |
| Red FOX Fine Foods Ltd | Hospitality | 2014 |
| Red FOX Resources Ltd | Other services | 2017 |
| Red FOX Southern Limited | Real estate | 2026 |
| Red Funnel Limited | Transport & logistics | 2017 |
| Red Hot Property Limited | Real estate | 2003 |
| Red Kite Cars & Commercials Ltd | Wholesale & retail | 2026 |
| Red Lion PUB Group Ltd | Hospitality | 2024 |
| Red Lodge Management (Chandlers Ford) Limited | Households | 1986 |
| Red Oak Builders Ltd | Construction | 2024 |
| Red Opal Ltd | Hospitality | 2026 |
| Red OWL Construction Limited | Construction | 2022 |
| Red Plaids Co Ltd | Wholesale & retail | 2024 |
| Red Rose BPO Ltd | Administrative & support | 2025 |
| Red Sky Inns Consultancy Ltd | Professional & scientific | 2012 |
| Red Smart Applications Ltd | Information & communication | 2018 |
| Red Souvenirs Limited | Wholesale & retail | 2014 |
| Red Square Medical Limited | Education | 2004 |
| Red Training & Consultancy Limited | Professional & scientific | 2003 |
| Red Volcano Limited | Professional & scientific | 2016 |
| RED4 Consulting Limited | Information & communication | 2014 |
| RED4 Property Limited | Real estate | 2021 |
| Redblack Recruitment Ltd | Administrative & support | 2014 |
| Redbookinternational Limited | Financial services | 2015 |
| Redbox Computer Solutions Limited | Information & communication | 1998 |
| Redbridge Bodyshop Ltd | Wholesale & retail | 2023 |
| Redcanvas Ltd | Manufacturing | 2012 |
| Redcourt (Southampton) Management Company Limited | Households | 1967 |
| Rede Galega UK Community Interest Company | Information & communication | 2019 |
| Redeem Properties Limited | Real estate | 2023 |
| Redenet Ltd | Information & communication | 2018 |
| Redfire Properties Limited | Real estate | 2022 |
| Redline Fire Safety Ltd | Professional & scientific | 2020 |
| Redline Technical Services Ltd | Manufacturing | 2025 |
| Redman Hudson Limited | Hospitality | 2018 |
| Redmer INK Ltd | Other services | 2018 |
| Redmer Limited | Financial services | 2023 |
| Redmesh Ltd | Information & communication | 2017 |
| Redshark Connect Ltd | Professional & scientific | 2025 |
| Redstone Cleaning Services UK Ltd | Administrative & support | 2026 |
| Redtech Security Ltd | Administrative & support | 2016 |
| Reducate UK Ltd | Financial services | 2024 |
| Redwade Developments Limited | Financial services | 2020 |
| Redwade Property Limited | Real estate | 2020 |
| Redwing Assets Ltd | Administrative & support | 2012 |
| Redwood Court Management Company Limited | Households | 2003 |
| Redwood Electrical Design Ltd | Construction | 2024 |
| Redz Scaffolding Limited | Construction | 2018 |
| Reecle Healthcare Ltd | Health & social care | 2015 |
| Reedfad Synergy Links Limited | Wholesale & retail | 2025 |
| Reedys Estate Agents Ltd | Real estate | 2022 |
| Reef and Roof Holding Ltd | Construction | 2026 |
| Reef View Apartments Limited | Hospitality | 2014 |
| Reefertrade Limited | Professional & scientific | 2018 |
| Reeltas Ltd | Real estate | 2019 |
| Rees Plastering Ltd | Construction | 2006 |
| Reevescorp Ltd | Construction | 2026 |
| Reevsey Properties Ltd | Real estate | 2025 |
| Reference C Limited | Information & communication | 2018 |
| Refin Ltd | Financial services | 2024 |