| S.Africa Capron Seaweed Co., Ltd | Cambridge | 2024 |
| S.Africa Roffe Agricultural Co., Ltd | Manchester | 2023 |
| S.C. Inspections (2023) Ltd | Norwhich | 2023 |
| S.E. Janel Ltd. | | 2007 |
| S.E.A. Survey Ltd. | London | 1999 |
| S.T. Drilling Ltd | Aberdeen | 2016 |
| S8R Ltd | Macclesfield | 2026 |
| SA Storey Limited | Bolton | 2010 |
| SA Storey North West Limited | Bolton | 2015 |
| SA11 Khan Limited | Middlesbrough | 2021 |
| Sabah Shell Petroleum Company Limited | | 1938 |
| Saexploration UK Limited | London | 2003 |
| SAF Electrical Services (NE) Ltd | Aberdeen | 2024 |
| Safe Access Services Limited | Redruth | 2006 |
| Safe Arms Safety Ltd | Darlington | 2014 |
| Safe Choice Consultancy Limited | Middlesbrough | 2019 |
| Safe Hands Inspection Limited | Aberdeen | 2013 |
| Safe OIL and GAS Services Ltd | Cardiff | 2025 |
| Safekick Limited | Wokingham | 2009 |
| Saferock Feed Ltd | Basildon | 2024 |
| Saferock Global Ltd | Basildon | 2026 |
| Saferock International Limited | Basildon | 2024 |
| Saferock Minerals Limited | Basildon | 2024 |
| Saferock Seed Capital Ltd | Basildon | 2024 |
| Safetec UK Limited | Aberdeen | 2003 |
| Safety Advisor K G Ltd | Peterhead | 2008 |
| Safety Control Services Ltd | Lauder | 2024 |
| Safety Right Ltd | Montrose | 2012 |
| Safewell Services Ltd | Glasgow | 2022 |
| Sagoe Enterprise Limited | London | 2016 |
| SAH Services NE Ltd | South Shields | 2018 |
| Sahara Geophysical Limited | Maidstone | 2013 |
| Sahel Resources Group Ltd | London | 2024 |
| Saimar Ventures Ltd | Paignton | 2020 |
| Saint Piran Exploration Ltd | London | 2025 |
| Saint-Gobain Construction Products UK Limited | Leicestershire | 1962 |
| Saiti Ltd | Sheffield | 2023 |
| Saka Indonesia Pangkah Limited | London | 1995 |
| Sakshi Resources Euro Holding Ltd | London | 2023 |
| Salama Petrochemical & OIL Company Ltd | London | 2011 |
| Salamander Energy (Bualuang Holdings) Limited | Liverpool | 2009 |
| Salamander Energy (S.E. Asia) Limited | Liverpool | 2005 |
| Salamander Energy Group Limited | Henley-On-Thames | 2004 |
| Salamander Energy Limited | Henley-On-Thames | 2006 |
| Salamander Production (UK) Limited | Westhill | 2020 |
| Salford Boilers Ltd | Swinton | 2020 |
| Salient Survey Ltd | Dollar | 2015 |
| Salinas Goldmine Limited | London | 1995 |
| Salineco Limited | Cardiff | 2019 |
| Salion Limited | Cheam | 2018 |
| Salop Sand & Gravel Supply Company Limited | Wellington | 1961 |
| Salop Sand and Gravel Limited | Telford | 2021 |
| Saloschin Limited | Huntingdon | 2007 |
| Salt and Mineral Suppliers Ltd | Southall | 2019 |
| Salt Melts UK Ltd | Manchester | 2026 |
| Saltend Magnet Metals Ltd | London | 2022 |
| Saltfleetby Energy Europe Limited | Isleworth | 2020 |
| Saltfleetby Energy Limited | London | 1969 |
| Saltire Drilling Tools Limited | Aberdeen | 2011 |
| Saltire Energy (Norway) Limited | Aberdeen | 2012 |
| Saltire Energy Limited | Aberdeen | 1996 |
| Saltire Jock Ltd | Inverurie | 2014 |
| Salum Salt Ltd | London | 2023 |
| SAM Exploration Consultants Limited | King'S Lynn | 2015 |
| Samadrock Ltd | Salford | 2024 |
| Sami Saad Kisha Ltd | London | 2025 |
| Samson Aggregates Ltd | Kingswinford | 2018 |
| Samson Structural Design Services Limited | Cardiff | 2018 |
| Samuel Gledhill & Sons Limited | Brighouse | 1949 |
| SAN Leon ELI Limited | London | 2020 |
| SAN Leon Energy (UK) Limited | London | 2013 |
| SAN Leon Holdings Limited | London | 2020 |
| SAN Leon OZA Limited | London | 2020 |
| SAN Phillips OIL & GAS Limited | Croydon | 2019 |
| SAN Technical Limited | West Kilbride | 2026 |
| San-Ed Ltd | London | 2011 |
| Sand and Stone Ltd | Brentwood | 2020 |
| Sand Energy Consulting Ltd | Mildenhall | 2023 |
| Sand Monitoring Services (Holdings) Limited | Aberdeen | 2008 |
| Sand Monitoring Services Limited | Aberdeen | 2004 |
| Sanda Mining Limited | Edinburgh | 2010 |
| Sandancer FM Ltd | South Shields | 2026 |
| Sandfire Spain Holdings Limited | London | 2021 |
| Sandfire Spain UK Limited | London | 2021 |
| Sandy Subsea Engineering Ltd | Cupar | 2010 |
| Sanika Resource Dynamics Ltd | Manchester | 2025 |
| Sannick Marine Ltd | Burra | 2024 |
| Santos (UK) Limited | London | 2013 |
| Santos Bangladesh Limited | Edinburgh | 1971 |
| Santos Sangu Field Limited | Edinburgh | 2003 |
| SAO Offshore Services Limited | Hull | 2012 |
| Sapphire and Carbuncle Energy Limited | Newport | 2025 |
| SAR Planning Services Limited | Sheffield | 2001 |
| SAR Safety Solutions Ltd | Hull | 2025 |
| Sara Norfolk Limited | Lowestoft | 2017 |
| Sarah Milne Associates Ltd | London | 2011 |
| Sarb Subsea Controls Ltd | Nottingham | 2014 |
| Sardar Haidary Limited | Manchester | 2017 |
| Sardinian Granite Company Ltd | London | 2020 |
| Sargacycle Ltd | Crawley | 2025 |