| Reco Store Limited | Wholesale & retail | 2019 |
| Recon-Ect Ltd | Information & communication | 2019 |
| Reconsultancy Limited | Financial services | 2025 |
| Records Management Girl Ltd | Information & communication | 2018 |
| Rectory Court (Marks TEY) Limited | Households | 1989 |
| Recurrent Energy Power Services UK Limited | Manufacturing | 2017 |
| Recycly Software Ltd | Information & communication | 2023 |
| Red Barn Close Management Company Limited | Administrative & support | 2014 |
| Red Barn Road Brightlingsea (Block C) Management Company Limited | Real estate | 1991 |
| Red Barn Road Brightlingsea (Block D) Management Company Limited | Households | 1991 |
| Red Barn Road Brightlingsea (Blocks a & B) Management Company Limited | Households | 1991 |
| Red Barn Road Brightlingsea (Open Space) Management Company Limited | Households | 1991 |
| Red Book Games Ltd | Information & communication | 2020 |
| Red FLY Interactive Ltd | Information & communication | 2021 |
| Red FOX Brewery Limited | Manufacturing | 2008 |
| Red Glazing Systems Ltd | Construction | 2016 |
| Red Hot Lettings Ltd | Real estate | 2013 |
| Red Hot Source (Elmstead) Ltd | Manufacturing | 2019 |
| Red Installations Limited | Construction | 2010 |
| Red Media Technologies Limited | Water & waste | 2014 |
| Red Oak Fires Limited | Other services | 2011 |
| Red Parrot Ltd | Wholesale & retail | 2024 |
| Red Pepper Marketing Ltd | Professional & scientific | 2001 |
| Red Plant Sales Limited | Wholesale & retail | 2002 |
| Red Plumbing & Heating Services Ltd | Construction | 2018 |
| Red Pool Limited | Professional & scientific | 2011 |
| Red Rock Estate & Property Management Limited | Real estate | 2009 |
| Red Rock Estate Agency Ltd | Real estate | 2020 |
| Red Rock PBS Limited | Real estate | 2010 |
| Red Seal Property Limited | Financial services | 2016 |
| Red Seal Resources Limited | Financial services | 2009 |
| Red SIX Aviation Ltd | Professional & scientific | 2021 |
| Red Spot (UK) Limited | Administrative & support | 2001 |
| Red Wolf Group Ltd | Administrative & support | 2024 |
| Red Yellow Blue Ltd | Wholesale & retail | 2023 |
| Red's Tattoo Parlour Limited | Other services | 2019 |
| Redbourne Wealth Management Ltd | Financial services | 2007 |
| Redbridge Design Ltd | Construction | 2021 |
| Redbridge Developments Limited | Construction | 2001 |
| Redbridge MED Limited | Professional & scientific | 2018 |
| Redbury Vineyard Ltd | Professional & scientific | 2001 |
| Reddy Traders Ltd | Wholesale & retail | 2023 |
| Redfish Business Solutions Ltd | Professional & scientific | 2023 |
| Redgate Construction Limited | Construction | 1994 |
| Redhead Couriers Limited | Transport & logistics | 2002 |
| Redhill Communications UK Ltd | Professional & scientific | 2022 |
| Redicus Limited | Professional & scientific | 2022 |
| Redimix Limited | Administrative & support | 2020 |
| Redlands House Limited | Health & social care | 2017 |
| Redlynch Property Management Limited | Administrative & support | 2021 |
| Redmae Ltd | Real estate | 2025 |
| Redmaynes Drive (Chelmsford) Management Company Limited | Households | 1988 |
| Redoor Education Ltd | Education | 2018 |
| Redswan Ventures Ltd | Education | 2023 |
| Redvine Properties Limited | Real estate | 2006 |
| Ree-Connect Ltd | Wholesale & retail | 2025 |
| Reece Owens Ltd | Real estate | 2026 |
| Reed Care Group Ltd | Health & social care | 2018 |
| Reed Care Homes Limited | Health & social care | 2008 |
| Reeds Place (Steeple Bumpstead) Management Company Limited | Households | 2022 |
| Reef Exotics Limited | Agriculture & fishing | 2017 |
| Reeman Dansie Limited | Administrative & support | 1997 |
| Reese Capital Holdings Limited | Professional & scientific | 2019 |
| Reese Energy Group Limited | Professional & scientific | 2021 |
| Reese Property Group Limited | Real estate | 2019 |
| Reese Property Management Limited | Real estate | 2019 |
| Reese Real Estate Holdings Limited | Professional & scientific | 2021 |
| Reese UK Property Limited | Real estate | 2019 |
| Reffell Carpentry Ltd | Construction | 2023 |
| Reffell Electrical Ltd | Construction | 2022 |
| Refined Edition Limited | Extraterritorial | 2018 |
| Reforge Tactical Ltd | Education | 2025 |
| Reformd Academy Ltd | Arts & recreation | 2026 |
| Refugee, Asylum Seeker & Migrant Action CIC | Health & social care | 2017 |
| Regain Turnaround Limited | Other services | 2017 |
| Regal Court NO. 5 Limited | Households | 2001 |
| Regal Court NO.3 Limited | Households | 2000 |
| Regal Housing Limited | Real estate | 2014 |
| Regan DE Wynter Productions Ltd | Arts & recreation | 2010 |
| Regatta Holdings Ltd | Financial services | 2016 |
| Regatta Offices (Freehold) Ltd | Construction | 2018 |
| Regatta Offices (Ipswich) Ltd | Construction | 2015 |
| Regdev Ltd | Professional & scientific | 2015 |
| Regency Decorators Ltd | Construction | 2016 |
| Regency Lodge (Jameson) Limited | Households | 1988 |
| Regency Oak Group Limited | Professional & scientific | 2024 |
| Regency Oak Landscapes Limited | Administrative & support | 2014 |
| Regency Place (Lexden Road) Management Company Limited | Real estate | 2026 |
| Regenerative Worklife Limited | Professional & scientific | 2023 |
| Regent Square (Black Notley) Limited | Construction | 2021 |
| Regent Square (Black Notley) Property Limited | Real estate | 2022 |
| Regent Square (Sheringham) Limited | Construction | 2022 |
| Regent Square Limited | Construction | 2014 |
| Regent Square Property Limited | Real estate | 2020 |
| Regroup-Solutions Limited | Administrative & support | 2024 |
| Regulatory Intellect Limited | Administrative & support | 2014 |
| Rehab Case Management Ltd | Health & social care | 2022 |
| Reid Plumbing & Heating Contractors Ltd | Construction | 2005 |
| Reid Property Developments Ltd | Construction | 2015 |
| Reidy's Holdings Limited | Financial services | 2021 |