| Salton Ltd | Professional & scientific | 2024 |
| Saltwater 60 Pentire Ltd | Real estate | 2009 |
| Salvage 2 Reborn Ltd | Wholesale & retail | 2019 |
| Sam's (Truro) Limited | Hospitality | 2016 |
| Sam's Diner Limited | Hospitality | 2016 |
| Sambells (Truro) Limited | Hospitality | 1999 |
| Sampson Gardens Management Company Limited | Extraterritorial | 1989 |
| Samssauna and Wellness Limited | Hospitality | 2017 |
| Samuel Eric Julian Limited | Extraterritorial | 2025 |
| Samuel Winn Ltd | Construction | 2015 |
| Sanctuary Massage Ltd | Other services | 2023 |
| Sand Bay Holiday Flats Limited | Hospitality | 2009 |
| Sanders a Limited | Professional & scientific | 2015 |
| Sandulika CIC | Education | 2024 |
| Sandy Lane Apartments (Carbis Bay) Management Company Limited | Households | 2012 |
| Sandy Lodge Developments Limited | Construction | 2021 |
| Sara LOW Holdings Limited | Professional & scientific | 2001 |
| Sara LOW Verification Limited | Arts & recreation | 2001 |
| Sarah B Properties Ltd | Real estate | 2019 |
| Sarah Gale Nutrition UK Limited | Health & social care | 2026 |
| Sati Project Ltd | Manufacturing | 2020 |
| Saving OUR Sarah CIC | Manufacturing | 2022 |
| Saxfield Ltd | Other services | 2022 |
| Sbpr Limited | Information & communication | 2006 |
| Scaffolding South West Limited | Construction | 1983 |
| Scaled Simple Ltd | Professional & scientific | 2026 |
| Scaleup Holdings Ltd | Real estate | 2024 |
| Scandium Partners Ltd | Professional & scientific | 2025 |
| Scarletts Well (Bodmin) Management Company Ltd | Households | 2015 |
| Scence Ltd | Manufacturing | 2018 |
| Scentstore Limited | Wholesale & retail | 2006 |
| SCF Hospitality Limited | Hospitality | 2024 |
| SCF Publican Limited | Hospitality | 2016 |
| Scope Surveying Ltd | Construction | 2019 |
| Scot-Tel Limited | Information & communication | 2004 |
| Scott and Company (Cornwall) Limited | Construction | 2003 |
| Scott and Company (Holdings) Limited | Financial services | 2016 |
| Scott Burridge Commercial LLP | | 2010 |
| SCR FIC Limited | Financial services | 2018 |
| Sculthorp Estates Limited | Hospitality | 2019 |
| Sculthorp Services Limited | Financial services | 2022 |
| Sea Breeze Trading Limited | Wholesale & retail | 2012 |
| Sea Change Cornwall Limited | Administrative & support | 2014 |
| Sea Gems Limited | Manufacturing | 1962 |
| Sea Goat Style House Ltd | Arts & recreation | 2023 |
| Sea Spray Holdings Limited | Other services | 2019 |
| Sea View Court (Property Management Company) Limited | Households | 2004 |
| Sea View Renovation Ltd | Construction | 2025 |
| Seabank Residents Management Company Limited | Real estate | 1998 |
| Seadrift Projects Limited | Construction | 2015 |
| Seagull Property Services Ltd | Construction | 2018 |
| Seaquestr Ltd | Information & communication | 2024 |
| Seascapes (Falmouth) Management Limited | Households | 2000 |
| Seasmiths Fish and Chips Ltd | Hospitality | 2019 |
| Seaways Diving Limited | Wholesale & retail | 2023 |
| Seawild Services Ltd | Arts & recreation | 2026 |
| Seawings Project Limited | Hospitality | 2018 |
| Secret LUX Ltd | Real estate | 2024 |
| Secure Forests CIC | Professional & scientific | 2020 |
| Secure Forests International Ltd | Information & communication | 2025 |
| Seedling Homes Ltd | Construction | 2023 |
| Sekhem Sauna & Recovery Ltd | Other services | 2026 |
| Sekuna Investments Ltd | Financial services | 2026 |
| Self Storage Cornwall Ltd | Transport & logistics | 2025 |
| Selignan Associates Ltd | Extraterritorial | 2012 |
| Sell Smart Business Solutions Ltd | Wholesale & retail | 2024 |
| Selven Homes Limited | Construction | 2019 |
| Sennen Health Limited | Information & communication | 2021 |
| Sentry Alarms (Cornwall) Ltd | Administrative & support | 2020 |
| Sercro Consultancy Limited | Administrative & support | 2022 |
| Serenity Fire Ltd | Public administration | 2022 |
| Serenity Swim Ltd | Education | 2025 |
| Serve Southwest Ltd | Hospitality | 2022 |
| Sesm Properties Ltd | Real estate | 2025 |
| SET Piece Limited | Construction | 1999 |
| Sevan (ST Mawes) Ltd | Other services | 2023 |
| Sexton Medical Services Limited | Construction | 2013 |
| SF Accountants SW Limited | Professional & scientific | 2021 |
| SG Global Property Ltd | Real estate | 2024 |
| Shaftricity Group Ltd | Construction | 2025 |
| Shapes GRP Limited | Extraterritorial | 2005 |
| Shaping Climate Vision CIC | Professional & scientific | 2022 |
| Sharkfin Media Limited | Professional & scientific | 2003 |
| Sharpness Wind Project Limited | Energy | 2014 |
| Sharpness Wind Project NO 2 Limited | Extraterritorial | 2009 |
| SHE Strides Limited | Arts & recreation | 2025 |
| Shee-Inns Ltd | Wholesale & retail | 2025 |
| Shelterbox Trading Limited | Wholesale & retail | 2009 |
| Shelterbox Trust | Health & social care | 2002 |
| Sheridan Works Ltd | Manufacturing | 2019 |
| Sherriff Designs Limited | Manufacturing | 2001 |
| Shivu Consultancy Ltd | Professional & scientific | 2026 |
| Shop Cornish Ltd | Professional & scientific | 2021 |
| Shore Partnership Limited | Real estate | 2019 |
| Shotgirls UK (Plymouth) Limited | Administrative & support | 2018 |
| Shotgirls UK (South) Limited | Administrative & support | 2018 |
| Shotgirls UK Ltd | Hospitality | 2017 |
| Shreeoom Limited | Hospitality | 2012 |
| Shuka Ltd | Real estate | 2025 |
| Siblinc Ltd | Administrative & support | 2018 |