| Regeneration (Hitchin) Limited | Construction | 2012 |
| Regent Cottage Hitchin Limited | Hospitality | 2024 |
| Regent Cottage Restaurant Limited | Real estate | 2026 |
| Regent Gardens (Stotfold) Management Company Limited | Real estate | 2009 |
| Regents Land Limited | Professional & scientific | 2006 |
| Regina Pasta Ltd | Hospitality | 2025 |
| Regina Pizza Ltd | Hospitality | 2025 |
| Reid Consulting Limited | Professional & scientific | 2019 |
| Reids Property Developments Limited | Construction | 2025 |
| Reinvent IT Limited | Information & communication | 2024 |
| Rejig Homes Ltd | Professional & scientific | 2019 |
| Relieved Healthcare Limited | Health & social care | 2023 |
| Relyt Digital Marketing Ltd | Professional & scientific | 2023 |
| Remac Group Limited | Construction | 2019 |
| Remarkable Tutoring Ltd | Education | 2011 |
| Remlap Trading Limited | Professional & scientific | 2021 |
| Remotespark Limited | Manufacturing | 1987 |
| Rendl Property Limited | Real estate | 2020 |
| Renew Direct Ltd | Wholesale & retail | 2025 |
| Rennworks Storage Limited | Transport & logistics | 2024 |
| Repair Technology Ltd | Administrative & support | 2010 |
| REPAIRS4UK Ltd | Wholesale & retail | 2021 |
| Resi Recruit Limited | Administrative & support | 2026 |
| Residential Cleaning Services Ltd | Administrative & support | 2021 |
| Residential Roofing & Repairs Limited | Construction | 2020 |
| Respond Plumbing and Heating Limited | Construction | 2023 |
| Response I.T. Services Limited | Information & communication | 1999 |
| Retail Boom Ltd | Professional & scientific | 2014 |
| Retail FIX Holdings Limited | Financial services | 2015 |
| Retail FIX Limited | Information & communication | 2004 |
| Retro Restored Ltd | Other services | 2012 |
| Revenue Agreement Services Ltd | Administrative & support | 2020 |
| Revive Recycled Plastics Ltd | Wholesale & retail | 2020 |
| Revride Limited | Professional & scientific | 2024 |
| RG Beattie (Beds) Limited | Construction | 2004 |
| Rgdscience Ltd | Professional & scientific | 2019 |
| RGM Global Consulting Limited | Professional & scientific | 2020 |
| RGM Global Logistics Ltd | Transport & logistics | 2025 |
| RGM Healthcare Services Limited | Health & social care | 2023 |
| RH UK Distribution Ltd | Wholesale & retail | 2021 |
| RHK Metals Ltd | Wholesale & retail | 2024 |
| Rhythms of the World | Arts & recreation | 2000 |
| Ricco Events Ltd | Administrative & support | 2017 |
| Rich Spirits Limited | Professional & scientific | 2023 |
| Richard Butler-Creagh Holdings Limited | Financial services | 2023 |
| Richard Harrison Bespoke Carpentry Ltd | Manufacturing | 2025 |
| Richard Kirby Photography Limited | Information & communication | 2009 |
| Richard Mensah Arts Ltd | Arts & recreation | 2022 |
| Richard Stickland Limited | Professional & scientific | 2019 |
| Richard Weber Ltd | Information & communication | 1997 |
| Richfield Consulting Ltd | Professional & scientific | 2017 |
| Ricketts Racing Limited | Wholesale & retail | 2019 |
| Rico Picante Limited | Manufacturing | 2010 |
| Ridge Line Roofing & HI Ltd | Construction | 2024 |
| Ridgewayscott Property Ltd | Real estate | 2024 |
| RIG Design Limited | Professional & scientific | 2020 |
| Rightghar Limited | Real estate | 2023 |
| Rightness Ltd | Administrative & support | 2022 |
| Rimford Estates Ltd | Construction | 2002 |
| Ringmo Limited | Wholesale & retail | 2024 |
| Ringstead Properties (Hitchin) Limited | Real estate | 2024 |
| RIS Healthcare Limited | Wholesale & retail | 2015 |
| Rise UP Development Ltd | Education | 2025 |
| Rising Medical Technologies Limited | Manufacturing | 2022 |
| Riteshield Roofing Limited | Construction | 2015 |
| Rive Accountancy Limited | Professional & scientific | 2003 |
| Riverside Developments (ST. Albans) Limited | Real estate | 1985 |
| RIZ Transport Ltd | Transport & logistics | 2020 |
| RJB Building & Interiors Ltd | Construction | 2017 |
| RJP Property Services Ltd | Administrative & support | 2023 |
| RJW Machinery Sales Ltd | Wholesale & retail | 2005 |
| RKB Property Investments Limited | Professional & scientific | 1976 |
| RKB Underwood Holdings Limited | Real estate | 1969 |
| RKK04 Holdings Limited | Financial services | 2022 |
| RKP and SON Consultancy Limited | Information & communication | 2024 |
| RKP and SON Property Consultancy Ltd | Real estate | 2025 |
| RLP Surveyors Holdings Ltd | Financial services | 2019 |
| RLP Surveyors Ltd | Professional & scientific | 2003 |
| RM & LF Enterprise Ltd | Wholesale & retail | 2025 |
| RMP Associates Limited | Professional & scientific | 2023 |
| Roadvacs Ltd | Administrative & support | 2013 |
| Roaming Bear Films Limited | Information & communication | 2024 |
| Roant Limited | Real estate | 2005 |
| Roasting Group Ltd. | Manufacturing | 2025 |
| Robert H Downes Limited | Professional & scientific | 1979 |
| Roberts & Hume Ltd | Real estate | 2025 |
| Robertson Design & Construction Ltd | Construction | 2009 |
| Robertson Lindsay Ltd | Administrative & support | 2010 |
| Robmel Limited | Professional & scientific | 2020 |
| Rock Health and Fitness Limited | Hospitality | 2016 |
| Rockahula Kids Limited | Wholesale & retail | 2013 |
| Rocket Juice Consulting Ltd | Professional & scientific | 2019 |
| Rocketgods Limited | Arts & recreation | 2016 |
| Rockpt Ltd | Hospitality | 2024 |
| Rocky Mountains Property Holding Limited | Financial services | 2015 |
| Roddy Ground Solutions Ltd | Construction | 2019 |
| Rodessa Realty (UK) Limited | Real estate | 2019 |
| Roger Storm Ltd | Real estate | 2021 |
| Rogers Bakery Limited | Manufacturing | 2006 |
| Rogersons Clearances Limited | Transport & logistics | 2019 |