| PROTEEZ2023 Ltd | Wholesale & retail | 2024 |
| PSB (Newmarket) Limited | Extraterritorial | 1984 |
| PSB Holdings Limited | Administrative & support | 1968 |
| PT ST Ives Ltd | Hospitality | 2024 |
| Punjab Haulage Ltd. | Transport & logistics | 2017 |
| Pure Cleaning Stives Ltd | Administrative & support | 2022 |
| Pure Valegro Ltd | Professional & scientific | 2023 |
| Pure Wisdom Consultancy Ltd | Professional & scientific | 2025 |
| Purser & Luxford Car Care Limited | Wholesale & retail | 2013 |
| Purser & Luxford Car Sales Limited | Wholesale & retail | 2012 |
| Putus Limited | Information & communication | 2015 |
| Q M Bathrooms Ltd | Construction | 2024 |
| Quality Leads Media Limited | Professional & scientific | 2020 |
| Quantum Electrical Installations Ltd | Construction | 2021 |
| Quantum Property Improvements Ltd | Other services | 2022 |
| Quattro Tech BSE Ltd | Wholesale & retail | 2024 |
| Quattro Tech Cars Ltd | Wholesale & retail | 2019 |
| Quattro-Tech Brand Limited | Wholesale & retail | 2022 |
| Quattro-Tech Cambridge Ltd | Wholesale & retail | 2020 |
| Quattro-Tech Ltd | Wholesale & retail | 2013 |
| Quattro-Tech Peterborough Ltd | Wholesale & retail | 2019 |
| Quattro-Tech Vanwerks Ltd | Wholesale & retail | 2020 |
| Quest Brothers Classic Cars Limited | Wholesale & retail | 2014 |
| Quest Brothers Classic Coachworks Limited | Wholesale & retail | 2015 |
| R & R Laundry Equipment Limited | Wholesale & retail | 1985 |
| R C Legal Solutions Limited | Administrative & support | 2016 |
| R Costings Limited | Administrative & support | 2003 |
| R G E Yate Limited | Manufacturing | 2004 |
| R Heath & Sons Funeral Services Limited | Professional & scientific | 2008 |
| R Lewis &SON Ltd | Real estate | 2019 |
| R P Welding Services Ltd | Manufacturing | 2008 |
| R S Nicoll Ltd | Wholesale & retail | 2013 |
| R&D Precision Limited | Professional & scientific | 2009 |
| R&F Properties Cambs Ltd | Real estate | 2025 |
| R. & H. Wale (Duxford) Limited | Construction | 2009 |
| R.O.I. Distribution Limited | Information & communication | 2002 |
| Race Borne Limited | Manufacturing | 2025 |
| Radlea Asset Management Limited | Information & communication | 2022 |
| Radlea Group Limited | Financial services | 2022 |
| Radlea Limited | Information & communication | 2007 |
| RAW GUN Limited | Manufacturing | 2013 |
| Raybon IT Consultancy Limited | Information & communication | 2015 |
| RB Accountancy Solutions Ltd | Professional & scientific | 2009 |
| RDS Heating & Renewables Ltd | Construction | 2015 |
| RDS Solar Ltd | Construction | 2023 |
| RDV Consulting Ltd | Professional & scientific | 2021 |
| RE Cleaning Limited | Administrative & support | 2025 |
| React Creator Ltd | Education | 2025 |
| Ready to Teach Cambridge Limited | Education | 2026 |
| READY2BUILD Construction Ltd | Construction | 2018 |
| Real World Solutions Ltd | Professional & scientific | 2022 |
| Realtime Sensing (UK) Limited | Administrative & support | 2020 |
| Realtime Sensing Limited | Administrative & support | 2020 |
| REC - Redeeming Every Community C.I.C. | Hospitality | 2018 |
| Reco Equipment Ltd. | Financial services | 2014 |
| Reco Hoist Ltd. | Manufacturing | 2014 |
| Recovr Navigating Life Ltd | Education | 2026 |
| Red Octopus Solutions Ltd | Professional & scientific | 2019 |
| Red World Media Limited | Information & communication | 2017 |
| Redstone Cloud Consulting Limited | Information & communication | 2022 |
| Redvers Consultancy Limited | Professional & scientific | 2026 |
| Reef Publishing Ltd | Information & communication | 2003 |
| Regen Products Limited | Wholesale & retail | 2021 |
| Regulus Publishing Ltd | Information & communication | 2024 |
| Rehman Prime Traders Ltd | Wholesale & retail | 2025 |
| Residential Property Partners Limited | Real estate | 2014 |
| Resolution Microscope Service Limited | Professional & scientific | 2003 |
| Resting Pets Limited | Other services | 2014 |
| Revell Turner & Wass Limited | Financial services | 2006 |
| Revenue Clicks Media Ltd | Extraterritorial | 2012 |
| Revive by Nutra Limited | Wholesale & retail | 2025 |
| Rewire Marketing Ltd | Information & communication | 2026 |
| Rexson Systems Limited | Extraterritorial | 2019 |
| Reynolds Generations Limited | Real estate | 2026 |
| RG10 Limited | Wholesale & retail | 2016 |
| RGA South Herts BJJ Ltd | Arts & recreation | 2021 |
| RGE Capital Limited | Manufacturing | 2012 |
| RGE Engineering Limited | Manufacturing | 2012 |
| RGE Operations Limited | Manufacturing | 2012 |
| RGE Tooling Limited | Manufacturing | 1979 |
| Rhino Management Consulting Limited | Professional & scientific | 2010 |
| RHM Cars Ltd | Wholesale & retail | 2024 |
| Rhymers Gate Limited | Households | 2024 |
| Richard Clark Consulting Limited | Professional & scientific | 2016 |
| Richard Green Property Maintenance Ltd | Construction | 2022 |
| Richard Laborne Carpentry and Joinery Limited | Construction | 2004 |
| Right Task Limited | Professional & scientific | 1993 |
| Rightmarket Limited | Information & communication | 2007 |
| Rileys Coffee Shop Ltd | Hospitality | 2022 |
| Ring Property Maintenance Ltd | Other services | 2022 |
| RIO Beauty & Barber Ltd | Other services | 2019 |
| Riverbank Psychology Services Limited | Health & social care | 2017 |
| Riverbank Trading and Holding Ltd | Financial services | 2026 |
| Rivermill House Management Company Limited | Real estate | 1997 |
| Riverport Business Clubs Limited | Other services | 2016 |
| Riverport Mews (Management Company) Ltd | Real estate | 2024 |
| Riverport Renovations & Construction Ltd | Construction | 2020 |
| Riverport Renovations (Cambridge) Ltd | Construction | 2026 |
| Riverside Close Residents Association Limited | Households | 2026 |
| Riverside Marine Services Ltd | Transport & logistics | 2021 |