| Supernova Energy Services Ltd | Norwich | 2020 |
| Suprun (UK) International Crop Nutrition Co., Ltd | Cardiff | 2025 |
| Surestream Petroleum Limited | London | 2004 |
| Surf Contractors Ltd | Aberdeen | 2016 |
| Surf Engineering Consultants Limited | Chobham | 2022 |
| Surprise International UK Group Co., Ltd | Stafford | 2023 |
| Survey Engineering Solutions Limited | Taunton | 2015 |
| Surveying and Directional Services Limited | Co Derry | 2006 |
| Susa Engineering & Consultancy Limited | Sandown | 2013 |
| Sussex Sandstone Limited | Chichester | 2003 |
| Sussex Sea Salt Company Limited | Seaford | 2026 |
| Sustain OIL and GAS Limited | London | 2012 |
| Sustainable Lithium Ltd | London | 2024 |
| Sustineri Group Ltd | Horley | 2021 |
| SV Engineering Consultancy Ltd | Reading | 2021 |
| Svalin Geoscience Limited | Weymouth | 2012 |
| SVO Energy Ltd | Redcar | 2026 |
| SW Offshore Electrical Limited | Blackpool | 2014 |
| Swagelining Limited | Glasgow | 2009 |
| Swala (UK) Limited | London | 2000 |
| Swala UK Operations Limited | London | 2026 |
| Swan Farm Minerals Ltd | Whitby | 2012 |
| Swan Rock Quarries Limited | Newry | 2006 |
| Sweden Kolher Mining and Chemicals Ltd | Cardiff | 2026 |
| Sweet Africa Trade Ltd | London | 2021 |
| Swel Services Limited | Inverurie | 2025 |
| Swellfix UK Limited | Eastleigh | 2007 |
| Swick Drilling Europe Limited | London | 2012 |
| Swiftdale Limited | Grantham | 1987 |
| Swiftpipe Ltd | Woking | 2008 |
| Swinlees Quarry Limited | Grangemouth | 2020 |
| Swinlees Quarrying Limited | Grangemouth | 2021 |
| Swiss Metal Trading Ltd | London | 2025 |
| Switch Metals PLC | London | 2021 |
| Sxsubsea Limited | Maidenhead | 2004 |
| Syaet Limited | Croydon | 2016 |
| Sykes Rigging Services Limited | Doncaster | 2014 |
| Sylvia Irene Wright Limited | Exeter | 2024 |
| Synergia Energy CCS Limited | London | 2019 |
| Synergia Energy Services UK Limited | London | 2021 |
| Synergia International Limited | London | 2025 |
| Synergy Diamond Products Ltd | Sheffield | 2021 |
| Synerisk Solutions Ltd | Aberdeen | 2025 |
| Synex Limited | Inverurie | 2021 |
| Syoncore Ltd | Hemel Hempstead | 2021 |
| Syreford Quarries & Masonry Limited | Cheltenham | 2005 |
| T & C Patterson Ltd | Newry | 2007 |
| T .S. Rees Holdings Limited | Bridgend | 2018 |
| T B M Controls Ltd | Aberdeen | 2012 |
| T E Djouadje Services Limited | Coventry | 2008 |
| T F M (UK) Limited | Strathclyde | 2007 |
| T J Environmental Limited | Fareham | 1999 |
| T J Fisher Consultancy Limited | Lowestoft | 2024 |
| T Marsh Ltd | St. Ives | 2002 |
| T Mulhern Aggregates Limited | Belfast | 2018 |
| T O'Connell & Sons (Contractors) Limited | Belfast | 1978 |
| T Spirit Ltd | Nottingham | 2021 |
| T. a. H Trading Limited | Astley, Tyldesley | 2013 |
| T. Brogan & SON Ltd | Omagh | 2019 |
| T. H. Moore (Contracts) Ltd | Newtownhamilton | 1996 |
| T. HAY Electrical Limited | Margate | 2016 |
| T.S. Rees (Tonmawr Quarry) Limited | Bridgend | 1989 |
| T.S. Rees Limited | Glam | 1964 |
| T.T. Surveys Limited | Padstow | 1985 |
| T2 Integrity Limited | Alford | 2000 |
| T2 Resources Limited | London | 2024 |
| T5 OIL & GAS Gabon Limited | Wokingham | 2014 |
| T5 OIL & GAS Ltd | Wokingham | 2013 |
| T5 OIL & GAS UK Limited | Wokingham | 2013 |
| TAB Trade Hire Ltd | Peterhead | 2018 |
| Tadeen International Limited | Bristol | 2021 |
| Taft Consultants Ltd | Brechin | 2023 |
| TAG Energy Group Limited | London | 2022 |
| Tailpro Consulting Limited | Bakewell | 2017 |
| Taipan Consulting International Ltd | London | 2019 |
| Taiyue International Trade Co., Limited | Cambridge | 2020 |
| Takas World Group Ltd | Harrow | 2023 |
| Talc Ltd | London | 2020 |
| Taldrwst CYF | Bangor | 2019 |
| Talent Mine International Ltd | Oldham | 2022 |
| Taline Limited | Peterborough | 2023 |
| Talisman (Jambi Merang) Limited | London | 1995 |
| Talisman Resources (North West Java) Limited | London | 2003 |
| Talisman UK (South East Sumatra) Limited | London | 1974 |
| TAM & Josh Associates Limited | Dartford | 2025 |
| TAM International North Sea Limited | Norwich | 1984 |
| TAM Mining Limited | London | 2017 |
| Tamboran Resources (UK) Limited | Belfast | 2010 |
| Taml Global Holding Ltd. | London | 2025 |
| Tamu Minerals Ltd | Beaconsfield | 2024 |
| Tancred Gravel Limited | Richmond | 1953 |
| Tangerine Gold Rock Limited | Salford | 2025 |
| Tangram Energy Ltd | London | 2017 |
| Tanico Ltd | London | 2021 |
| Tanikes Global Ltd | Southsea | 2023 |
| Tanin Builders Limited | Bournemouth | 2025 |
| Tankology Ltd | Cardiff | 2016 |
| Tantalum Mining Ventures Limited | Harrow | 2022 |
| TAO Operations Limited | Chatham | 2019 |
| Tapvoch Mining PLC | Wolverhampton | 2018 |