| Simon Hall International Ltd | Transport & logistics | 2024 |
| Simons & Taylor Building Contractors Limited | Construction | 2012 |
| Simpkins Edwards Audit LLP | | 2018 |
| Simpkins Edwards LLP | | 2010 |
| Simpkins Edwards Services Limited | Professional & scientific | 1987 |
| Simple 3D Ideas Ltd | Manufacturing | 2025 |
| Simple Media and Advertising Ltd | Professional & scientific | 2018 |
| Simple UNI Storage Ltd | Other services | 2014 |
| Simpleweb Limited | Information & communication | 2006 |
| Simply Housing Solutions Ltd | Real estate | 2025 |
| Simply Sealants Limited | Construction | 2015 |
| Simply Sublime Ltd | Wholesale & retail | 2019 |
| Simply Switchgear Limited | Professional & scientific | 2011 |
| Simplylingerie Limited | Extraterritorial | 2009 |
| Sims Business Ltd | Professional & scientific | 2023 |
| Singh Radiology Service Ltd | Health & social care | 2023 |
| Singing for Snorers Ltd | Information & communication | 2022 |
| Single PLY Structure Holdings Limited | Financial services | 2023 |
| Single PLY Structures Limited | Construction | 2011 |
| Single Pringle Mingle Ltd | Manufacturing | 2024 |
| Sino-Celtic (UK) Ltd. | Construction | 1995 |
| SIP N Paint Cotswolds Limited | Hospitality | 2026 |
| Sirius 36 Trading Limited | Administrative & support | 2017 |
| Sisi OSA Ltd | Wholesale & retail | 2025 |
| Sisidoit Ltd | Health & social care | 2026 |
| Sisters Homes Ltd | Real estate | 2025 |
| Site Engineers Exeter Ltd | Construction | 2024 |
| Sito Corporation Limited | Information & communication | 2011 |
| Situ Living Ltd | Administrative & support | 2008 |
| Situ Ltd | Administrative & support | 2019 |
| Siva and Sons Ltd | Wholesale & retail | 2020 |
| SIX Degrees Group Limited | Other services | 2019 |
| SIX Harmony Limited | Information & communication | 2024 |
| SIX Scoops Limited | Professional & scientific | 2021 |
| Sixell Ltd | Professional & scientific | 2024 |
| Sjaj Plumridge Ltd | Hospitality | 2019 |
| SJB Decor Ltd | Construction | 2019 |
| SJB Lettings Ltd | Real estate | 2018 |
| SJI Creatives Ltd | Arts & recreation | 2025 |
| Sjkk Coatings Limited | Manufacturing | 2017 |
| SJL Security Ltd | Administrative & support | 2019 |
| SJM Optimisation Solutions Ltd | Information & communication | 2025 |
| SJP Independent Educational Psychology Services Limited | Education | 2015 |
| SK Food (Ukbd) Ltd | Hospitality | 2023 |
| Skala Camping Ltd | Hospitality | 2020 |
| SKC Holdings Ltd | Real estate | 2023 |
| Skegness Solar Park Limited | Energy | 2013 |
| Skin Masters Academy Ltd | Education | 2021 |
| Skinner Sloan Limited | Financial services | 2014 |
| Skip the Skip Limited | Water & waste | 2023 |
| Skulltec Hair Loss SMP Southwest Ltd | Other services | 2019 |
| Sky Holdings (South West) Ltd | Real estate | 1961 |
| Skyblue Aero Connect Limited | Transport & logistics | 2025 |
| Skyblue Aero Simulation Limited | Transport & logistics | 2023 |
| Skybreeze Ltd | Wholesale & retail | 2025 |
| Skylark House Block Management Limited | Households | 2024 |
| Skyline Ridge Ltd | Real estate | 2024 |
| Skylineweb Ltd | Transport & logistics | 2024 |
| Skynexe Limited | Information & communication | 2023 |
| Skynexe Technology Limited | Information & communication | 2023 |
| Skypark Development Partnership LLP | | 2009 |
| SL Quantity Surveying (SW) Limited | Professional & scientific | 2015 |
| SLA IT Solutions Limited | Information & communication | 2017 |
| Slabstand Ltd | Wholesale & retail | 2025 |
| Slac Marketing Ltd | Information & communication | 2025 |
| Slackjaw Theatre CIC | Education | 2019 |
| Slade & Sons Limited | Wholesale & retail | 1951 |
| Slade Group Holdings Limited | Financial services | 2021 |
| Slater Inspections Limited | Other services | 2017 |
| Slaterhope Limited | Professional & scientific | 2016 |
| Sleeping Moon Ltd | Hospitality | 2024 |
| Sleepyhead Clinic Ltd | Health & social care | 2014 |
| Slewton Limited | Administrative & support | 2019 |
| Slf.Community Ltd | Wholesale & retail | 2022 |
| Slievenamon Agricultural Services Ltd | Agriculture & fishing | 2024 |
| Slime Labs Limited | Wholesale & retail | 2019 |
| SLJ Group Holdings Ltd | Financial services | 2025 |
| Sloanes Estates SW Limited | Real estate | 2003 |
| Sloe Bakery Ltd | Manufacturing | 2024 |
| Slow Burn Ltd | Information & communication | 2022 |
| Slqs Exeter Limited | Professional & scientific | 2024 |
| SLS Homes Ltd | Real estate | 2023 |
| Slsgb Training Limited | Education | 2004 |
| Slsm Limited | Real estate | 2020 |
| Sluman's Bars and Catering Limited | Hospitality | 2025 |
| SLV Construction Ltd | Construction | 2019 |
| SM Glam Lounge Ltd | Other services | 2024 |
| SMA Building & Roofing Ltd | Construction | 2023 |
| SMA Storage Ltd | Real estate | 2026 |
| SMA Surfacing Ltd | Construction | 2018 |
| Smafs Limited | Hospitality | 2026 |
| Small Business Services SW Ltd | Other services | 2024 |
| Smallholdr Ltd | Information & communication | 2017 |
| Smart (Millerson) Limited | Real estate | 2012 |
| Smart Brick Services Ltd | Construction | 2022 |
| Smart EA Exeter Sales Limited | Real estate | 2023 |
| Smart Endeavors Limited | Households | 2020 |
| Smart Estate Agent Limited | Real estate | 2014 |
| Smart Evolution Limited | Manufacturing | 2019 |
| Smart Financial Services Ltd | Financial services | 2021 |