| Rusev Limited | Real estate | 2016 |
| Ruth NIC an Eanaigh Limited | Health & social care | 2015 |
| Ruza Services Ltd | Wholesale & retail | 2022 |
| RWS Re-Wired Systems Ltd | Administrative & support | 2023 |
| S & J Bodyrepairs (Pembrokeshire) Limited | Wholesale & retail | 2016 |
| S a Saunders & SON Limited | Construction | 2020 |
| S and J Edwards Painters and Decorators Limited | Construction | 2017 |
| S F Engineering Consultancy Ltd | Professional & scientific | 2017 |
| S G Dorn Construction Limited | Construction | 2014 |
| S Kimsey Consulting Limited | Construction | 2020 |
| S.J. Waite & Company Limited | Construction | 2000 |
| S.P.S.P.A. Ltd | Extraterritorial | 2024 |
| S.T.E.A.M. Flight Academy Limited | Education | 2024 |
| S7 Events Limited | Arts & recreation | 2022 |
| S7 Fitness Limited | Arts & recreation | 2015 |
| Safe Wind Access Technician Ltd | Manufacturing | 2019 |
| Safety 1ST Training Ltd | Arts & recreation | 2021 |
| Safety Services Organisation - Mort Limited | Manufacturing | 2018 |
| Safety Services Organisation - Professional Engineering Ltd | Professional & scientific | 2018 |
| Safety Services Organisation Ltd | Professional & scientific | 2018 |
| Saffron Inn Ltd | Hospitality | 2026 |
| Saffron Kichen Limited | Hospitality | 2025 |
| Saga Systems LLP | | 2018 |
| Sahra’S International Ltd | Administrative & support | 2025 |
| Salt & City Property Group Ltd | Real estate | 2025 |
| Salt Loft Wellbeing CIC | Health & social care | 2024 |
| Salters Blinds Limited | Manufacturing | 2011 |
| Saltminster Limited | Real estate | 1981 |
| Saltwind Properties Ltd | Real estate | 2025 |
| Saludann Ltd | Extraterritorial | 2024 |
| Samuel Troth Limited | Households | 2025 |
| Sancler Limited | Professional & scientific | 2004 |
| Sandstone Brands Ltd | Administrative & support | 2017 |
| Sarah Hamilton Mortgage Services Limited | Other services | 2016 |
| Sardasst Ltd | Other services | 2022 |
| Sbbc (Pembs) Ltd | Administrative & support | 2023 |
| SC Skin Care Limited | Other services | 2021 |
| Scale Accommodation Ltd | Hospitality | 2026 |
| Scale Portables Ltd | Wholesale & retail | 2025 |
| Schmidt Medical Limited | Extraterritorial | 2019 |
| Science Assist Ltd | Information & communication | 2025 |
| Scoot Enterprises Ltd | Administrative & support | 2015 |
| Scorers Soccer Academy Ltd | Administrative & support | 2023 |
| Scott Crawford & Sons Automotive Limited | Wholesale & retail | 2026 |
| Scott Trevett Ltd | Professional & scientific | 2021 |
| SCS Associates UK Ltd | Construction | 2006 |
| Seakayak Guides Ltd | Arts & recreation | 2023 |
| Sean O'Neill Bricklaying Limited | Construction | 2023 |
| Seaview Mini Market (BH) Limited | Wholesale & retail | 2013 |
| Seaworthy Surveys Ltd | Transport & logistics | 2020 |
| Security Lettings Management & Rentals Ltd | Administrative & support | 2017 |
| Sedum Commerce LP | | 2017 |
| Seilio Limited | Manufacturing | 2019 |
| Seren Dawel Ltd | Hospitality | 2026 |
| Sgrinhouse Ltd | Manufacturing | 2021 |
| Shabuniku UK Limited | Hospitality | 2016 |
| Shackleton & Sons Contracting and Hire Services Ltd | Agriculture & fishing | 2020 |
| Share the Care With Laura Ltd | Health & social care | 2023 |
| Share the Community Ltd | Health & social care | 2025 |
| Shearwater Consulting Engineers Ltd | Professional & scientific | 2021 |
| Shelfie Ltd | Transport & logistics | 2015 |
| Sherman Properties Ltd | Households | 2022 |
| Shermans(Wales) Limited | Agriculture & fishing | 1990 |
| Ship Inn Trefin Limited | Hospitality | 1989 |
| Shipping Oriental Services Limited | Administrative & support | 2005 |
| SHM Electrical Services (Wales) Limited | Construction | 2014 |
| Shortlands Leisure Ltd | Hospitality | 2019 |
| Shortwave Audio (Holdings) Ltd | Extraterritorial | 2014 |
| Shortwave Audio Ltd | Manufacturing | 2014 |
| Shot Logistics LP | | 2018 |
| Showpeace Sports & Events Ltd | Administrative & support | 2025 |
| Shruuya Solutions Ltd | Information & communication | 2022 |
| Silbers CIC | Education | 2017 |
| Silentspirit Ltd | Administrative & support | 2023 |
| Silver Stoves Ltd | Construction | 2023 |
| Silverdale Close Management Company Limited | Households | 2015 |
| Silversoul Ltd | Administrative & support | 2024 |
| Simon Davies Construction Limited | Construction | 2012 |
| Simon Watson (Pembs) Limited | Other services | 2005 |
| Simply Coffee Mobile Limited | Hospitality | 2011 |
| Sirius Life Solutions Ltd | Extraterritorial | 2025 |
| SJ Jones School Run Limited | Transport & logistics | 2003 |
| Sj's Catering Pembs Limited | Hospitality | 2022 |
| SJV Property Limited | Real estate | 2024 |
| Skikida Ltd | Administrative & support | 2022 |
| Skokholm Property Services Ltd | Real estate | 2021 |
| Skybound Therapies Limited | Health & social care | 2018 |
| Slade Lane (Haverfordwest) Management Limited | Households | 2020 |
| Slate Yard Limited | Administrative & support | 2003 |
| SLE Europe Ltd | Administrative & support | 2022 |
| Sleekstone Private Clients Ltd | Financial services | 2019 |
| Slipscreens Limited | Manufacturing | 2010 |
| Slipstream Impact Ltd | Extraterritorial | 2019 |
| SM Selfmade Ltd | Administrative & support | 2025 |
| Smart Bookkeeping Ltd | Professional & scientific | 2010 |
| Smartsimplelife Ltd | Extraterritorial | 2022 |
| Smartsimpleliving Ltd | Extraterritorial | 2022 |
| Smith Fabrication Ltd | Manufacturing | 2016 |
| Smoke Meat Vendor Ltd | Hospitality | 2025 |
| Snowdrop Health Ltd | Real estate | 2024 |