| Riverside Reformer Pilates Limited | Arts & recreation | 2026 |
| RLB Motor Company Limited | Wholesale & retail | 2004 |
| RLT Built Environment Limited | Professional & scientific | 2006 |
| RMA Structural Design Ltd | Professional & scientific | 2021 |
| Rmsh (2012) Limited | Manufacturing | 2012 |
| Rnbdevelopmentsandconstruction Limited | Construction | 2025 |
| Road JET Private Hire Ltd | Transport & logistics | 2024 |
| ROB Love Consulting Limited | Professional & scientific | 2023 |
| Robinsons Holiday Cottage’S Ltd | Construction | 2025 |
| Rock and Saltwater Limited | Manufacturing | 2017 |
| Rock Architects Ltd | Financial services | 2024 |
| Rock Design Limited | Professional & scientific | 2023 |
| ROI Holdings Limited | Information & communication | 2005 |
| ROI Software Distribution Limited | Information & communication | 2005 |
| ROI Software LLP | | 2012 |
| Roman Gate Maintenance Ltd | Administrative & support | 2025 |
| Romano's ST. Ives LLP | | 2011 |
| Rooted Land and Property Limited | Real estate | 2024 |
| Rose Morocco Store LLP | | 2009 |
| Rosewall Meadow Ltd | Hospitality | 2019 |
| Rosstechnix Ltd | Professional & scientific | 2006 |
| Rostrevor One Limited | Real estate | 2015 |
| Rotherhill Construction Ltd | Construction | 2006 |
| Rotherhill Holdings Limited | Construction | 2016 |
| Round the Bend Ltd | Construction | 2014 |
| Roxane Minerals Limited | Mining & quarrying | 2012 |
| Roysian Security Limited | Administrative & support | 2026 |
| RR Plant Hire Limited | Construction | 2021 |
| RS MGT Ltd | Administrative & support | 2023 |
| RS Properties & Management Ltd | Real estate | 2024 |
| RT Solbiz Limited | Administrative & support | 2014 |
| RTP Holdings Ltd | Real estate | 2017 |
| Rugeley Court Management Company Limited | Households | 1989 |
| RWF Productions Ltd | Professional & scientific | 2022 |
| Rydal Networks Limited | Information & communication | 2008 |
| S & S Landscaping Contractors Limited | Mining & quarrying | 2021 |
| S a V Motors Limited | Wholesale & retail | 2004 |
| S and S Developments Building Co. Limited | Construction | 1988 |
| S E Hase Transport Limited | Transport & logistics | 2010 |
| S G Moore Property Services Ltd | Real estate | 2026 |
| S J Brett Property Limited | Real estate | 2024 |
| S J Property Services Ltd | Construction | 2015 |
| S Miller Property Services Ltd | Real estate | 2025 |
| S&T Silver Ltd | Wholesale & retail | 2023 |
| S.A. Collective Ltd | Other services | 2021 |
| Saanj Group Ltd | Professional & scientific | 2024 |
| Sabi Jewels Limited | Manufacturing | 2024 |
| Sachak Consulting Ltd | Professional & scientific | 2024 |
| Safepeak Roofing Limited | Construction | 2026 |
| Safety Training and Consultancy Services Ltd | Education | 2021 |
| SAI Baba Cars Ltd | Transport & logistics | 2021 |
| Sail Lofts Management Limited | Households | 2020 |
| Saint Ives Electrical Contractors Limited | Construction | 2025 |
| Saints Boardriders Limited | Administrative & support | 2016 |
| Saints Funeral Services Ltd | Other services | 2014 |
| Saleha Williams Ltd | Professional & scientific | 2023 |
| Sales and Surveys Ltd | Construction | 2020 |
| Salt Estate Agents Ltd | Real estate | 2020 |
| Saltwater ST Ives Limited | Hospitality | 2018 |
| SAM Simpson Bookkeeping Ltd | Professional & scientific | 2019 |
| SAM Terry Developments Ltd | Construction | 2024 |
| Sampson Electrical Services Ltd | Construction | 2026 |
| Sanders Fish & Chips Ltd | Hospitality | 2003 |
| Santos Therapies Ltd | Health & social care | 2021 |
| Sapient Projects Limited | Information & communication | 2016 |
| Sath 24 Ltd | Professional & scientific | 2024 |
| Savage Pro Ltd | Construction | 2022 |
| SAY NO to Sunnica Action Group Ltd | Other services | 2021 |
| SCG Prestige Payroll Ltd | Professional & scientific | 2021 |
| Scoff Troff Cafe Limited | Hospitality | 2015 |
| Scotts of Cambridge Ltd | Professional & scientific | 2012 |
| Screen, Scratch and Stitch Limited | Manufacturing | 2021 |
| SD Construction and Developments Ltd. | Construction | 2010 |
| Sea Buck Limited | Manufacturing | 2018 |
| Sea of Coffee Limited | Hospitality | 2021 |
| Seagull House (ST. Ives) Limited | Households | 1992 |
| Seahorse Associates Ltd. | Education | 2012 |
| Secretary First Ltd | Administrative & support | 2022 |
| Secure Audit Limited | Professional & scientific | 2024 |
| Secure Home Purchase (2014) Limited | Real estate | 2014 |
| Secure Home Purchase (2015) Limited | Real estate | 2014 |
| Seiten UK Co Limited | Wholesale & retail | 2022 |
| Self Help Digital Limited | Administrative & support | 2010 |
| Sellco PARTNERS22 Ltd. | Hospitality | 2022 |
| Sensawave CIC | Other services | 2026 |
| Sentio Inclusive Ltd. | Administrative & support | 2022 |
| Serene Energy Ltd | Construction | 2023 |
| Serojo Limited | Information & communication | 2005 |
| Serve 1 Limited | Education | 2025 |
| Service IS a Bonus Limited | Wholesale & retail | 2025 |
| Sesseto Limited | Information & communication | 2012 |
| Seven & Five Ltd | Manufacturing | 2021 |
| SF Topco Limited | Professional & scientific | 2021 |
| Sflt Limited | Wholesale & retail | 2012 |
| Shakespeare Road Flats (ST. Ives) Limited | Households | 1976 |
| Shaktiism C.I.C. | Wholesale & retail | 2019 |
| Shara Limited | Administrative & support | 2010 |
| Sharper B2B Marketing Limited | Professional & scientific | 2020 |
| Shaw Telecom Services Ltd | Information & communication | 2018 |
| Sheaf Street Health Store Limited | Wholesale & retail | 2016 |