| Smith's Limestone Limited | Oxford | 1973 |
| Smiths Concrete Limited | Maidenhead | 1957 |
| SMS Inspection and Rope Access Ltd | Tonypandy | 2019 |
| SMW Elec Limited | Runcorn | 2014 |
| Snikrep Limited | Radlett | 2013 |
| Snobell Operations Ltd | Ellon | 2014 |
| Snowfox Discovery Ltd | Oxford | 2023 |
| Snowhill Stone Ltd | Wigton | 2014 |
| Snsem Limited | Chipping Norton | 2021 |
| SNSEM2 Limited | Chipping Norton | 2021 |
| Snydale Plant Limited | Pontefract | 2017 |
| SO Babs International Limited | Cardiff | 2024 |
| Soccerazzi UK Ltd | Fulham | 2019 |
| Soda World Ltd | London | 2018 |
| Sodumase Mining International Limited | Cardiff | 2021 |
| Sogel Ltd | Glasgow | 2024 |
| Soil Hill Quarries (Yorkshire) Limited | Leeds | 2017 |
| Soil Hill Quarries Limited | Bradford | 2015 |
| Soil Hill Restoration Limited | Bradford | 2023 |
| Sojitz OIL & GAS (Egypt) Limited | London | 2005 |
| Soland Mining Investment Holdings Ltd | Sheffield | 2025 |
| Solaris Exploration Limited | Uckfield | 2009 |
| Solaris Marine (Holdings) Limited | Cramlington | 2017 |
| Solgold PLC | London | 2005 |
| Solid Rock Solutions Cumbria Limited | Carnforth | 2018 |
| Solids Control Services Limited | Aberdeen | 2010 |
| Soliton Resources Limited | Twickenham | 2017 |
| Solo Oilfield Services Limited | Lowestoft | 1998 |
| Solucity OIL and GAS Limited | London | 2018 |
| Solutions Consult Ltd | Erith | 2012 |
| Solv Limited | Fort William | 2003 |
| Solvak Engineers Limited | Bushey | 2001 |
| Somerset Stone Supplies Limited | Castle Cary | 2019 |
| Sona Engineering Ltd | Aberdeen | 2016 |
| Sondex Wireline Limited | Farnborough | 1998 |
| Sonmar Solutions Ltd. | Inverurie | 2008 |
| Sool Mineral Ltd | London | 2025 |
| Sorm Limited | Southampton | 2019 |
| Sound Energy Meridja Limited | London | 2016 |
| Sound Energy Morocco South Limited | London | 2016 |
| Sound Energy New Ventures Limited | London | 2019 |
| Sound Energy PLC | London | 2005 |
| Souter Inspection Services Ltd. | Aberdeen | 2016 |
| South Africa Alidy Biotechnology Co., Ltd | Beckenham | 2023 |
| South Africa Cape Algae Research and Development Co., Ltd | Cardiff | 2026 |
| South Africa Shuofute Crop Nutrition Co., Ltd | Cambridge | 2024 |
| South African Coal Limited | London | 2006 |
| South Crofty Limited | Truro | 2007 |
| South Tyne Drilling Limited | Washington | 2004 |
| South West Materials Limited | Coventry | 2005 |
| South Western Energy Limited | Bridgend | 2012 |
| Southampton Marine Laboratory (UK) Co., Ltd | Cambridge | 2025 |
| Southern Cross Britannia Limited | London | 2017 |
| Southern Cross Britannia Services Ltd | London | 2019 |
| Southern Cross Royalties Limited | London | 2009 |
| Southern Gravel Limited | London | 2003 |
| Southern Point Resources Ltd | London | 2022 |
| Southern Reservoir Engineering Limited | Dorchester | 1996 |
| Southfields Gravel Company Limited | Essex | 1964 |
| Southlands Exploration Ltd | Sheffield | 2017 |
| Southview Interiors Ltd | Chobham | 2007 |
| Southworth Quarry Limited | Otley | 1992 |
| Sowax LEE Group Ltd | Milton Keynes | 2015 |
| Sowtragroup Ltd | London | 2026 |
| Sp-Tehnologija.Lv Ltd | London | 2021 |
| Space Mined Ltd | Edinburgh | 2024 |
| Space Technologies Limited | Enfield | 2020 |
| Spain Baudar Chemical Company Ltd | Cardiff | 2026 |
| Spain Cosado Chemical Co., Ltd | London | 2024 |
| Spain Gabiguard Plant Nutrition Co., Ltd | Manchester | 2026 |
| Spain KMT BIO Co., Ltd | Coventry | 2025 |
| Spain Laka International Chemcial Industry Ltd | Manchester | 2024 |
| Spain Lepu Group Co., Ltd | Cambridge | 2026 |
| Spain Obeli Crop Nutrition Co., Ltd | Cambridge | 2026 |
| Spain Porgia Biochemical Co., Ltd | Beckenham | 2023 |
| Spain Quiglo Chemical Co., Ltd | Cardiff | 2026 |
| Spain Schnauer Crop Nutrition Co., Ltd | Cambridge | 2025 |
| Spain Seagate Plant Nutrition Co., Ltd | Cambridge | 2025 |
| Spain Yunmu Crop Nutrition Ltd | Cambridge | 2021 |
| Spaniard Hall Excavations Limited | Shelf, Halifax | 1995 |
| Spanish Spain Hochen Agriculture Co., Ltd | Cambridge | 2024 |
| Sparkin Engineering Ltd | Middlesbrough | 2024 |
| Spartek Systems UK Ltd | Kintore | 2004 |
| SPC Subsea Ltd | Montrose | 2021 |
| Special Metal Alloys UK Ltd | Bolton | 2020 |
| Special Tech Lifting Ltd | London | 2020 |
| Specialist Access Fabrications (2013) Limited | Wallsend | 2013 |
| Specialist Access Onshore/Offshore Ltd | Lowestoft | 2024 |
| Specialist Access Technicians Limited | Bonnyrigg | 2013 |
| Specialist Coating (Scotland) Limited | Westhill | 2017 |
| Specialist Explosive Services Contracts Limited | Nottingham | 2000 |
| Specialist Explosive Services Limited | Nottingham | 1974 |
| Specialist Plant Diagnostics Ltd | Glasgow | 2024 |
| Specialist RIG Surveys Limited | Kincardineshire | 2002 |
| Speciality Carbons Limited | Neath | 2003 |
| Specialty Commodities Supply Chains UK Ltd | Greater London | 2024 |
| Specsus Ltd | London | 2024 |
| Spectre Global Trading Limited | London | 2025 |
| Spectrum Energy Commercial Consultants Ltd | Bristol | 2015 |
| Spectrum Engineering Limited | Mansfield | 2003 |