| Slate Seas Creative Ltd | Information & communication | 2020 |
| Solway Precast Limited | Manufacturing | 2012 |
| Solway Precast Products Ltd. | Manufacturing | 2012 |
| SOSN2025 Limited | Wholesale & retail | 2025 |
| Spicy Girlz Ltd | Hospitality | 2025 |
| ST Colmon Preservation Trust Company | Real estate | 2022 |
| Stevenson Farms Ltd | Agriculture & fishing | 2016 |
| Stonefield Contract Farming Ltd | Agriculture & fishing | 2019 |
| Straid Farms Limited | Agriculture & fishing | 1963 |
| Strathhavon Caravan Park (Girvan) | Hospitality | 1960 |
| Strathhavon Limited | Hospitality | 2014 |
| SWS Trading Ltd | Construction | 2026 |
| Tamside Limited | Energy | 2015 |
| Technical Web Marketing Limited | Information & communication | 2000 |
| THE Ballantrae Trust | Other services | 2017 |
| THE Barn-Burnhead Ltd | Wholesale & retail | 2025 |
| THE Girvan Bargain Store Limited | Wholesale & retail | 2023 |
| THE Girvan Paper Shop Ltd | Wholesale & retail | 2023 |
| THE Hamilton Arms Girvan Ltd | Hospitality | 2020 |
| THE Harbour Cafe Limited | Hospitality | 2011 |
| THE Hendrick's GIN Distillery Limited | Manufacturing | 2002 |
| THE Lion of Carrick Ltd | Hospitality | 2026 |
| THE New Cafe Royale Limited | Hospitality | 2022 |
| THE Westcoast House Ltd | Construction | 2019 |
| THIRTY20 Limited | Hospitality | 2026 |
| Thomas Murray Property Ltd | Real estate | 2020 |
| Tidal Pumping and Hydro Limited | Energy | 2018 |
| Tonys Enterprises Limited | Transport & logistics | 2019 |
| Trae Bakes Limited | Wholesale & retail | 2020 |
| Trossachs Trout Limited | Real estate | 1995 |
| TS Shearlaw & Sons Limited | Agriculture & fishing | 2018 |
| Turnberry Restorations Limited | Manufacturing | 2015 |
| Turnberry RUG Works Trustees Limited | Manufacturing | 2013 |
| Urban & Rural Contractors Ltd | Construction | 2020 |
| Urban & Rural Electrical Limited | Construction | 2015 |
| Victor One SIX Consultancy Ltd | Administrative & support | 2019 |
| View Productions Ltd. | Information & communication | 2016 |
| WA Services & Solutions Ltd | Professional & scientific | 2023 |
| WE HAE Meat Limited | Wholesale & retail | 2008 |
| Weldpro-Qual Limited | Manufacturing | 2015 |
| WEN Qing 688 Ltd | Hospitality | 2023 |
| What a Load of Rubbbish Limited | Water & waste | 2023 |
| Whiteminhill LLP | | 2021 |
| WHM Renewables Limited | Energy | 2020 |
| Wildings Restaurant Limited | Hospitality | 2001 |
| Wishes FAE Girvan Ltd | Wholesale & retail | 2026 |
| Woodland Bay Equestrian Ltd | Agriculture & fishing | 2017 |
| Yasmin Cuisine Ltd | Hospitality | 2023 |