| Robertson Marine Ltd | Professional & scientific | 2010 |
| Robertsons Training Ltd | Education | 2025 |
| Rocname Ltd | Agriculture & fishing | 2026 |
| Ross Bremner Transport Ltd | Manufacturing | 2016 |
| Ross Joinery Ltd | Construction | 2010 |
| RS Agri Services Ltd | Agriculture & fishing | 2022 |
| RS Group Management Ltd | Financial services | 2024 |
| Rumster Outdoor Centre Management Group | Health & social care | 2005 |
| Rypeco Ltd | Hospitality | 2020 |
| S.I.D. Building Services Limited | Construction | 2004 |
| Sabz Spice Ltd | Hospitality | 2018 |
| Sams Furniture Ltd | Wholesale & retail | 2008 |
| Sandy Fraser Plumbing Limited | Construction | 2002 |
| Scribe Partners Limited | Information & communication | 2022 |
| SD Electrical Ltd | Construction | 2022 |
| SDG Consultations Limited | Construction | 2019 |
| Second World WAR Air Raid Victims - Wick | Administrative & support | 2004 |
| Sh.Watten Ltd | Real estate | 2024 |
| Shefa Telecom Limited | Information & communication | 2018 |
| Sheldon Shellfish Ltd | Agriculture & fishing | 2017 |
| Simply Bliss Limited | Wholesale & retail | 2013 |
| Simpson Oils Limited | Wholesale & retail | 1996 |
| Sinclair (Holdings) Limited | Financial services | 2023 |
| Sinclair Bay Engineering Services Limited | Extraterritorial | 1998 |
| Sinclair Bay Group Properties Limited | Households | 2023 |
| Sinclair Bay Inspection Services Ltd | Mining & quarrying | 2022 |
| Sinclair Glazing and Joinery Limited | Construction | 2013 |
| SJB Solutions Ltd | Mining & quarrying | 2021 |
| SJE Project Control Solutions Limited | Professional & scientific | 2015 |
| Solunahair Limited | Other services | 2025 |
| Somerset Interiors Ltd | Construction | 2023 |
| Sparkle and Shine Caithness Cleaning Services Ltd | Administrative & support | 2026 |
| Spice Masala Wick Ltd | Hospitality | 2026 |
| Spotless Management Ltd | Administrative & support | 2026 |
| ST Fergus Bowling Club Ltd | Arts & recreation | 2021 |
| Steven Inspection Services Limited | Professional & scientific | 2024 |
| Stewart Fishing Co Ltd | Extraterritorial | 2021 |
| Stroma Technical Services Ltd | Mining & quarrying | 2019 |
| Stroma Wildlife Cruises Ltd | Transport & logistics | 2025 |
| Sutherland Brothers Limited | Wholesale & retail | 1984 |
| Sutherland Construction Ltd | Construction | 2019 |
| T Prewett T/A Victoria Sandwich Ltd | Hospitality | 2023 |
| Taste North Limited | Other services | 2013 |
| Thai Scaffolding Ltd | Construction | 2026 |
| THE Kinsale Stone Co Wales Limited | Administrative & support | 2003 |
| THE Kitchen Place Limited | Wholesale & retail | 2014 |
| THE Langley Collection Ltd | Hospitality | 2026 |
| THE Laurandy Centre | Health & social care | 2010 |
| THE Lighthouse Agency Limited | Professional & scientific | 1997 |
| THE Pulteney Group Limited | Extraterritorial | 2004 |
| THE Shore Bistro Ltd | Hospitality | 2026 |
| Thermohaus Ltd | Professional & scientific | 2018 |
| Thistle Building & Roughcasting Ltd | Construction | 2022 |
| TL Science Ltd | Professional & scientific | 2010 |
| Tony's Fire & Stove Ltd | Construction | 2025 |
| Trading AS Number 11 Ltd | Wholesale & retail | 2013 |
| Turner Lamont Services Ltd | Administrative & support | 2006 |
| Vegalot Limited | Agriculture & fishing | 2026 |
| Victor T Fraser & Co Limited | Professional & scientific | 2013 |
| Vitality Retreat LLP | | 2008 |
| West Watten Engineering Ltd | Extraterritorial | 2014 |
| Whaligoe Catering Ltd | Hospitality | 2020 |
| Wick Bicycle Repairs and Servicing Ltd | Other services | 2024 |
| Wick Development Trust | Other services | 2019 |
| Wick Players | Arts & recreation | 2003 |
| Wick Spice Ltd | Hospitality | 2018 |
| Windtech Marine Consultancy Scotland Ltd | Professional & scientific | 2020 |
| Yhtiö Limited | Professional & scientific | 2018 |