| Seafood Bistro Ltd | Hospitality | 2023 |
| Select Shapes Limited | Real estate | 1958 |
| Sennen Investments Limited | Financial services | 2021 |
| Sensory-Stuff Ltd | Wholesale & retail | 2024 |
| Sharepointwulf Limited | Information & communication | 2012 |
| Shepherd Outdoors Ltd | Wholesale & retail | 2024 |
| SID Vale Court Management Company Limited | Households | 1975 |
| SID Vale Metal Craft Ltd | Construction | 2018 |
| SID Valley (Educational) Ltd | Education | 2022 |
| SID Valley Butchers Ltd | Manufacturing | 2025 |
| SID Valley Cars Ltd | Transport & logistics | 2005 |
| SID Valley Decorators Ltd | Construction | 2014 |
| SID Valley Garage Limited | Wholesale & retail | 2006 |
| SID Valley Radio Ltd | Information & communication | 2017 |
| SID Valley Stoves Ltd | Construction | 2024 |
| SID Valley Tree Surgery Limited | Agriculture & fishing | 2006 |
| Sidford Cross (Sidford) Limited | Real estate | 2009 |
| Sidlife Limited | Hospitality | 1963 |
| Sidmouth 140 Limited | Hospitality | 2022 |
| Sidmouth Amateur Dramatic Society Limited | Arts & recreation | 2006 |
| Sidmouth Barber Ltd | Other services | 2020 |
| Sidmouth BED & Mattress Centre Limited | Wholesale & retail | 2019 |
| Sidmouth Body Repairs Limited | Wholesale & retail | 2008 |
| Sidmouth Coastal Community Hub CIC | Other services | 2013 |
| Sidmouth Craft Hub Limited | Wholesale & retail | 2022 |
| Sidmouth Deckchair Hire Limited | Administrative & support | 2026 |
| Sidmouth Fairleigh Management Limited | Real estate | 2012 |
| Sidmouth Folk Festival C.I.C. | Arts & recreation | 2005 |
| Sidmouth Folk Week Limited | Arts & recreation | 2005 |
| Sidmouth Garage Limited | Wholesale & retail | 2011 |
| Sidmouth GIN Ltd. | Wholesale & retail | 2017 |
| Sidmouth Golf Club Limited | Arts & recreation | 2019 |
| Sidmouth Hotels Holdings Limited | Financial services | 2017 |
| Sidmouth Lifeboat | Other services | 2004 |
| Sidmouth Old Vicarage Limited | Households | 1984 |
| Sidmouth Osteopaths Limited | Health & social care | 2004 |
| Sidmouth Pets Limited | Wholesale & retail | 2012 |
| Sidmouth Restaurants Limited | Hospitality | 2012 |
| Sidmouth RFC Trading Limited | Arts & recreation | 2017 |
| Sidmouth Riding Livery Ltd | Arts & recreation | 2020 |
| Sidmouth Rugby Football Club Limited | Arts & recreation | 2011 |
| Sidmouth Seaside Holidays Limited | Real estate | 2023 |
| Sidmouth Self Catering Limited | Hospitality | 2026 |
| Sidmouth Town AFC Supporters Group Ltd | Arts & recreation | 2016 |
| Simon Alexander (UK) Ltd | Wholesale & retail | 2007 |
| Simon Winston Ltd | Real estate | 2023 |
| Simpkin Commercial Limited | Real estate | 2026 |
| Simpkin Properties Limited | Real estate | 2019 |
| SKS Metal Recycling Ltd | Wholesale & retail | 2020 |
| Sleepyhead Consultancy Ltd | Health & social care | 2025 |
| Snail London Property Ltd | Real estate | 2019 |
| Somatic Systems Ltd | Information & communication | 2025 |
| Someday Something Ltd. | Hospitality | 2017 |
| Something Lovely Pottery Ltd | Arts & recreation | 2019 |
| South Oak Design Limited | Construction | 2025 |
| South Oak Limited | Professional & scientific | 2020 |
| South West Serviced Accommodation Limited | Hospitality | 2016 |
| Southcoast Liquid Screeding Ltd | Construction | 2021 |
| Sova Group (UK) Ltd | Water & waste | 2010 |
| Sova Group Limited | Extraterritorial | 2021 |
| Space Hair Design Ltd | Other services | 2026 |
| Spaceful Ltd | Hospitality | 2022 |
| Srfc Events Co Limited | Hospitality | 2024 |
| ST Blanes Ltd | Professional & scientific | 2025 |
| ST. Helens Management Company Limited | Administrative & support | 1989 |
| ST. Johns Healthcare (Devon) Limited | Health & social care | 2013 |
| ST. Peters Court Sidmouth (Management) Company Limited | Households | 1993 |
| Stadway Meadow Management Company Limited | Real estate | 2016 |
| Stanhope Drive Property Owners Company Ltd | Extraterritorial | 2015 |
| Stowford Community Centre CIC | Arts & recreation | 2010 |
| Strathdon Property Investments | Real estate | 1963 |
| Strivehub Ltd | Other services | 2023 |
| Summerhill Lyme Regis Limited | Households | 1990 |
| Summit Events Limited | Other services | 1994 |
| Support Hive Ltd | Information & communication | 2024 |
| Surrey Hills Estates Development Limited | Construction | 2015 |
| Sustainability Frontiers Community Interest Company | Education | 2009 |
| Sutl Limited | Professional & scientific | 2025 |
| Swann Business Park Ltd. | Administrative & support | 2020 |
| Sweetcombe Cottage Holidays Limited | Hospitality | 2002 |
| Sweetcombe Cottages Ltd | Hospitality | 2025 |
| Sweethill Eco Fort Ltd | Agriculture & fishing | 2023 |
| Swell Media Limited | Information & communication | 2008 |
| SWH Bar Ltd | Hospitality | 2025 |
| Symmetry Health Ltd | Health & social care | 2019 |
| T & B Property Maintenance Ltd | Construction | 2011 |
| Taluca Management Ltd | Households | 2026 |
| Taraman Holdings Limited | Real estate | 2026 |
| TBI Sidmouth Ltd | Hospitality | 2025 |
| Team CRE8 Ltd | Arts & recreation | 2012 |
| Technical Product Ltd | Wholesale & retail | 2009 |
| Temple Design Studio Ltd | Professional & scientific | 2026 |
| Tendril Technologies Ltd | Information & communication | 2026 |
| THE Car Consultancy Ltd | Transport & logistics | 2025 |
| THE Cinnamon Tree (Sidmouth) Ltd | Hospitality | 2013 |
| THE Courtyard Sidmouth Ltd | Hospitality | 2019 |
| THE Crafty Cook C.I.C. | Hospitality | 2023 |
| THE Dispatches Company Limited | Manufacturing | 2024 |
| THE Donkey Sanctuary Trustee Limited | Administrative & support | 2010 |
| THE EAR WAX Clinic Ltd | Health & social care | 2020 |