| Saltwater Digital Limited | Information & communication | 2025 |
| Samostrat Ltd | Professional & scientific | 2023 |
| Sand&Palm Ltd | Wholesale & retail | 2019 |
| Sanders Farm Shop Ltd | Wholesale & retail | 2025 |
| Sanderson Management Services Limited | Professional & scientific | 2014 |
| Sandpiper Cottages Management Company Limited | Households | 2013 |
| Sandy Paws Dog Walking Cornwall Ltd | Other services | 2025 |
| Sandy Rocks (Mawgan Porth) Limited | Households | 1984 |
| Sandylands Yard Ltd | Real estate | 2017 |
| Sandylodge Management Company Ltd | Households | 2025 |
| Sapien-X Global Ltd | Wholesale & retail | 2026 |
| Sarah's Kards Limited | Wholesale & retail | 2015 |
| Saunassa Events Ltd | Other services | 2025 |
| Saunassa Franchise Limited | Other services | 2025 |
| Saunassa Ltd | Other services | 2023 |
| Saunassa Perranporth Ltd | Other services | 2026 |
| Save Money Save Tax Limited | Information & communication | 2012 |
| Scampus Holdings Ltd | Financial services | 2025 |
| Scampus Property Ltd | Real estate | 2025 |
| Scarlet Hotel Limited | Hospitality | 2003 |
| Schmid Kitchens Limited | Wholesale & retail | 2020 |
| Scoobybits Limited | Wholesale & retail | 2006 |
| SE Crest Property Limited | Real estate | 2019 |
| Sea Engineering Solutions Limited | Professional & scientific | 2010 |
| Sea ME Sports Ltd | Education | 2023 |
| Sea Spray Cornwall Limited | Other services | 2018 |
| Seabase Limited | Manufacturing | 1995 |
| Sean Porter (Padstow) Limited | Agriculture & fishing | 2019 |
| Seaquest RTM Company Limited | Households | 2023 |
| Search HOG Ltd | Professional & scientific | 2019 |
| Seaspace Porth Limited | Hospitality | 2003 |
| Seaspray Holiday Management Ltd | Hospitality | 2020 |
| Seatoys Limited | Extraterritorial | 2015 |
| Secretgardennewquay Ltd | Hospitality | 2021 |
| Secure Alarms Limited | Administrative & support | 2017 |
| Seek the Mystique Ltd | Manufacturing | 2025 |
| SEF Heating & Plumbing Ltd | Construction | 2020 |
| SEF Holdings (Newquay) Ltd | Real estate | 2021 |
| Segway Limited | Arts & recreation | 2019 |
| Select Cornwall Ltd. | Other services | 2015 |
| Send Excellence Ltd | Education | 2025 |
| Serendipity SW Ltd | Other services | 2021 |
| Servicewatch Limited | Real estate | 1995 |
| Seventeen Trading Ltd | Hospitality | 2022 |
| Sextant Advisory Services Limited | Administrative & support | 2019 |
| Seymour AV Limited | Real estate | 2017 |
| SGA Fitness Limited | Arts & recreation | 2022 |
| SGA Holdings Ltd | Construction | 2019 |
| SH48 Ltd | Extraterritorial | 2022 |
| Shack and Poolside Limited | Hospitality | 2025 |
| Shack Developments Ltd | Construction | 2018 |
| Shedlife Limited | Manufacturing | 2023 |
| Sheersense Ltd | Wholesale & retail | 2011 |
| Shelter Suite Ltd | Information & communication | 2023 |
| Shiva Cafe Ltd | Hospitality | 2022 |
| Shiva Studio Ltd | Other services | 2023 |
| SHJ Ventures Ltd | Professional & scientific | 2024 |
| Shore Health Ltd | Health & social care | 2023 |
| Shore Surf Lodge Ltd | Hospitality | 2017 |
| Shoreline Flats Management Company Limited | Households | 2002 |
| Shoreline Holiday Home Management Ltd | Hospitality | 2026 |
| Shoreline Talent Ltd | Administrative & support | 2025 |
| Shoshan Limited | Arts & recreation | 2002 |
| Siddiqui (Cornwall) Limited | Professional & scientific | 2007 |
| Siding Developments Ltd | Construction | 2021 |
| Silent Disco Newquay Limited | Arts & recreation | 2022 |
| Silver-Tongued Devil Limited | Manufacturing | 2023 |
| Silverkey Management Limited | Real estate | 2022 |
| Silverwell Group Ltd | Wholesale & retail | 2025 |
| Simmons Inns Limited | Hospitality | 2019 |
| Simply Bakes by FIG Ltd | Wholesale & retail | 2023 |
| Simply Blue Energy (Orkney) Limited | Energy | 2015 |
| Simply Blue Energy Wind Limited | Energy | 2017 |
| Simply Generators Ltd | Wholesale & retail | 2010 |
| Sing Galaxy 168 Limited | Hospitality | 2021 |
| Sirius Black International Ltd | Hospitality | 2023 |
| Sitesunny Property Management Limited | Households | 2000 |
| SJ Thomas Electrical (Cornwall) Ltd | Construction | 2025 |
| SJM Healthcare Training & Consultancy Ltd | Information & communication | 2021 |
| SK Landscaping Ltd | Administrative & support | 2006 |
| Skinclinica Ltd | Health & social care | 2026 |
| Skinner’S Brewing Company (Cornwall) Limited | Manufacturing | 2023 |
| Skye Law Ltd | Professional & scientific | 2024 |
| Skyloo Rope Access Ltd | Construction | 2026 |
| Skymatics Ltd. | Professional & scientific | 2019 |
| Slaphead Ltd | Information & communication | 2007 |
| Slate Cellars Limited | Wholesale & retail | 2022 |
| Slingshot Aerospace Ltd | Information & communication | 2013 |
| SLK Engineering Services Ltd | Manufacturing | 2023 |
| Small Wonders Newquay Limited | Other services | 2010 |
| Smart Personal Development Limited | Education | 2026 |
| Smart Seller Ltd | Information & communication | 2019 |
| SMG Management (Bodmin) Ltd | Households | 2009 |
| SMH Civils & Utility Services Ltd | Construction | 2026 |
| Smile and Shine Studio Limited | Health & social care | 2026 |
| SMV Electrical Ltd | Construction | 2020 |
| SND Decorators Ltd | Construction | 2020 |
| Sofala Cornwall Ltd | Hospitality | 2025 |
| Solon OS Ltd | Manufacturing | 2023 |
| Sonnyfran Limited | Hospitality | 2012 |