| Rural Computing Limited | Information & communication | 2011 |
| Rural Security Solutions Ltd | Administrative & support | 2024 |
| S Andrews Roofing and Building Services Limited | Construction | 2025 |
| S Day Scrap Metals & Contracting Ltd | Wholesale & retail | 2025 |
| S W Plastic (Norfolk) Ltd | Construction | 2017 |
| Safer Driving Education Ltd | Education | 2023 |
| Safety Revolution (Eastern) Ltd | Professional & scientific | 2017 |
| Safety Revolution Ltd | Professional & scientific | 2003 |
| Safety Source Limited | Professional & scientific | 2022 |
| Sapient Talent Limited | Administrative & support | 2023 |
| Sarah Boult Dental Ceramics Limited | Health & social care | 2013 |
| Saschuk Ltd | Hospitality | 2023 |
| Saxon Agriculture Limited | Wholesale & retail | 1998 |
| Scaling UP Coaches Limited | Administrative & support | 2025 |
| Schenn Properties Ltd | Real estate | 2017 |
| Scid Associates Ltd | Professional & scientific | 2021 |
| Scribe (Norfolk) Ltd | Education | 2019 |
| Scrimshaws Consultancy Limited | Professional & scientific | 2023 |
| SD Microsystems Limited | Professional & scientific | 2000 |
| Sdari Barbers Ltd | Other services | 2021 |
| SDB Holdings Group Ltd | Financial services | 2026 |
| Securely Agile Limited | Information & communication | 2000 |
| SENTINEL25 Ltd | Education | 2025 |
| Serella Holdings Ltd | Real estate | 2023 |
| Seriously Interesting Management Limited | Hospitality | 2016 |
| Setasi Consulting Limited | Extraterritorial | 2015 |
| Setasi Holdings Limited | Administrative & support | 2014 |
| Seven Peaks Consulting Limited | Professional & scientific | 2022 |
| Shallcross Partners Limited | Professional & scientific | 2018 |
| Shapes & Shades Consultancy Limited | Professional & scientific | 2024 |
| Shaun Clarkson ID Limited | Arts & recreation | 2005 |
| Sheri Laizer Ltd | Information & communication | 2026 |
| Shout-Out Limited | Hospitality | 1999 |
| Shuttleworth Property Management Co. Limited | Real estate | 1993 |
| Simon Oliver Services Limited | Manufacturing | 2011 |
| Sleep Health Ltd | Health & social care | 2017 |
| Sleephealth Solutions Limited | Health & social care | 2020 |
| Smart Megawatt Stack Fuel Cell Systems Limited | Manufacturing | 2021 |
| Smithandhowegroup Ltd | Wholesale & retail | 2025 |
| Snack on Site Limited | Hospitality | 2009 |
| Soft Idiom Limited | Information & communication | 2001 |
| Solarcrown Europe Limited | Wholesale & retail | 2011 |
| Sopwith Aviation Limited | Manufacturing | 2021 |
| Sopwith Limited | Manufacturing | 2021 |
| Sowwif Ltd | Professional & scientific | 2015 |
| Sparrow's Trinket Trove Ltd | Wholesale & retail | 2026 |
| SPH (Norfolk) Limited | Construction | 2000 |
| SPH Specialist Services Limited | Manufacturing | 2014 |
| Spring Thinking (UK) Limited | Professional & scientific | 2017 |
| Sprinta Logistics Ltd | Transport & logistics | 2020 |
| Ssl-Stoves Limited | Other services | 2025 |
| SSW Electrical Services Limited | Construction | 2015 |
| ST Barts. Clothing Ltd | Wholesale & retail | 2026 |
| ST John’S Care Ltd | Health & social care | 2023 |
| Stacked Barrels Ltd | Wholesale & retail | 2026 |
| Stamford HR Solutions Ltd | Administrative & support | 2012 |
| Stanford Butters Ltd | Construction | 2018 |
| Starlings of Swaffham Limited | Wholesale & retail | 2002 |
| Starvalley Limited | Real estate | 1982 |
| Staycations Direct Ltd | Hospitality | 2025 |
| Steak in the Stix Limited | Hospitality | 2019 |
| Stewart’S Developments Limited | Construction | 2024 |
| Stonegate House (Management) Limited | Administrative & support | 1987 |
| Storage Hunters Ltd | Administrative & support | 2024 |
| Stork Holdings Ltd | Real estate | 2022 |
| Storm Coatings Ltd | Construction | 2018 |
| Stott EC Limited | Construction | 2022 |
| Stratagem OPS Limited | Extraterritorial | 2015 |
| Stratec Business Contracts Limited | Administrative & support | 1998 |
| Stratos Cbrn Consulting Ltd | Professional & scientific | 2025 |
| Strattons Farm (Swaffham) Management Company Limited | Administrative & support | 2001 |
| Street Leisure Limited | Other services | 2011 |
| Strident Innovations Ltd | Manufacturing | 2012 |
| Suiter Developments Limited | Construction | 2013 |
| Super Human Partners Limited | Other services | 2022 |
| Supernature Pet Ltd | Manufacturing | 2023 |
| Surviving Retirement Limited | Extraterritorial | 2013 |
| Sutcliffe Motorcycles Limited | Wholesale & retail | 2010 |
| SVC (Swaffham) Properties Limited | Real estate | 2021 |
| Swaffham & District Mental Health Association Limited | Health & social care | 1994 |
| Swaffham & Litcham Home Hospice Support Limited | Health & social care | 2001 |
| Swaffham Fencing Limited | Wholesale & retail | 2012 |
| Swaffham Golf Club Ltd | Arts & recreation | 2024 |
| Swaffham HCW Ltd | Administrative & support | 2023 |
| Swaffham Renovate & Build Ltd | Construction | 2024 |
| Swaffham Rugby Football Club Limited | Arts & recreation | 2010 |
| Swaffham Stoves Limited | Other services | 2020 |
| Swaffham Sushi Ltd | Hospitality | 2025 |
| Swaffham Veterinary Centre Limited | Professional & scientific | 2015 |
| SYC Corporation Limited | Administrative & support | 2023 |
| Syndew Limited | Real estate | 1973 |
| T Waterson Ltd | Construction | 2022 |
| T. D. a. C. Services Limited | Professional & scientific | 2017 |
| T. M. T. Technologies Limited | Agriculture & fishing | 2005 |
| T.T.S.R. Limited | Administrative & support | 2003 |
| T2E Ltd | Professional & scientific | 2018 |
| Tablebark Limited | Hospitality | 2007 |
| Taigh Duitseach Ltd | Hospitality | 2021 |
| Tanks-Uk Limited | Manufacturing | 2016 |
| Task and Finish Limited | Administrative & support | 2023 |