| Ryall on Ropes Ltd | Construction | 2025 |
| S Carr Go Ltd | Information & communication | 2024 |
| S Enterprises Ltd | Real estate | 2021 |
| S Zarrar & Co. Ltd | Professional & scientific | 2026 |
| S&P (Henley-On-Thames) Ltd | Professional & scientific | 2020 |
| S.A.Kailas Ltd | Professional & scientific | 2018 |
| Safa Restaurant (London) Limited | Hospitality | 2011 |
| Sagoss Limited | Information & communication | 2006 |
| Saint Helens Milling Company Limited | Construction | 1951 |
| Salamander Energy Group Limited | Mining & quarrying | 2004 |
| Salamander Energy Limited | Mining & quarrying | 2006 |
| SAM Butler Garden Design Limited | Extraterritorial | 1993 |
| Sanbei Phoneshop Ltd | Wholesale & retail | 2025 |
| Sandford Fields Residents Management Company Limited | Households | 2006 |
| Sandford Mill (Freehold) Limited | Households | 1994 |
| Sandford Mill Limited | Professional & scientific | 1995 |
| Sandford Mill Management Limited | Households | 1984 |
| Santiago Araya Polo Limited | Agriculture & fishing | 2024 |
| Santo Antao Property Co Limited | Real estate | 2010 |
| Sara Copeland Interiors Ltd | Professional & scientific | 2019 |
| Saros Technology Limited | Professional & scientific | 1992 |
| Sash Window Holdings Ltd | Construction | 2020 |
| Sash Window Rescue Limited | Construction | 2012 |
| Satec Service Limited | Water & waste | 2012 |
| Savile ROW Travel Limited | Administrative & support | 2006 |
| Savvy Sausage Ltd | Professional & scientific | 2023 |
| SB UK PAY Limited | Construction | 2024 |
| Sbpk FX Limited | Administrative & support | 2024 |
| Scallywag Travel Limited | Administrative & support | 2003 |
| Scarewaves Productions Ltd | Information & communication | 2024 |
| Scarp Landscape Architecture Ltd. | Professional & scientific | 2013 |
| Scienceworx Ltd | Professional & scientific | 2025 |
| Scott Cohen Solicitors Limited | Professional & scientific | 2015 |
| Screaming Frog Limited | Professional & scientific | 2010 |
| SDB Strategic Planners Limited | Financial services | 1984 |
| Sea Bunkering Holding Limited | Professional & scientific | 1996 |
| Sea Bunkering Limited | Wholesale & retail | 1991 |
| Sea Transportation Limited | Transport & logistics | 2012 |
| Seaforth Lodge Management Company (Seaton) Limited | Households | 1985 |
| Sean Roberts Ltd | Hospitality | 2023 |
| Secantor Business Services Limited | Professional & scientific | 2017 |
| Secret Raves Limited | Hospitality | 2026 |
| Selfhood Studios Ltd | Information & communication | 2022 |
| Selfhood Technologies Limited | Information & communication | 2024 |
| Senator High Wycombe Limited | Households | 1989 |
| Sennen Design International Ltd | Professional & scientific | 2016 |
| Seox Limited | Health & social care | 2015 |
| Serena Richards Interiors Limited | Manufacturing | 2005 |
| Serge Cador L'Ebeniste Limited | Manufacturing | 2002 |
| Sermon Lane Nominees Limited | Extraterritorial | 1969 |
| Sevenex Farm Ltd | Real estate | 2024 |
| Sevo Consultancy Ltd | Professional & scientific | 2016 |
| SG2A Global Consulting Ltd | Professional & scientific | 2025 |
| SGP Oxford Management Ltd | Households | 2015 |
| Shannon Construction Limited | Construction | 1994 |
| Shannon Haulage Limited | Transport & logistics | 1994 |
| Shannon Property Limited | Extraterritorial | 2022 |
| Shannon Training Limited | Administrative & support | 2005 |
| Shaw & Sons (Builders) Ltd | Construction | 2014 |
| Shelley Close London Limited | Real estate | 2021 |
| Shelph AI Limited | Information & communication | 2026 |
| Sheriff Mobility CIC | Health & social care | 2025 |
| Sheriff Property Group Ltd | Real estate | 2025 |
| Shiplake Court Limited | Education | 1958 |
| Shop at Stocks Ltd | Wholesale & retail | 2017 |
| Shorelines RGR Limited | Hospitality | 2016 |
| Shpc Holdings Limited | Extraterritorial | 2022 |
| Shutterhouse Ltd | Information & communication | 2025 |
| Sian Esther Ltd | Wholesale & retail | 2018 |
| Sidneycat Limited | Other services | 2023 |
| Sierra Wireless (UK) Limited | Information & communication | 2001 |
| Sika Inns Ltd | Hospitality | 2023 |
| Silver and Honey Limited | Information & communication | 2023 |
| Silverstone Escapade Holding Ltd | Real estate | 2021 |
| Simon Blackwell Consulting Ltd | Administrative & support | 2024 |
| Simon Mack Architecture Ltd | Professional & scientific | 2011 |
| Simple Smart Ltd | Wholesale & retail | 2022 |
| Simple Space Build Ltd | Construction | 2021 |
| Simplespace Design Ltd | Construction | 2019 |
| Simpson Research Limited | Extraterritorial | 1965 |
| Simwise Limited | Information & communication | 2025 |
| Sinclair Regulatory Consulting Ltd | Professional & scientific | 2023 |
| Sion Physio and Sports Performance Ltd | Health & social care | 2018 |
| SIP IT Ltd | Wholesale & retail | 2025 |
| Sirene Wine Company Ltd | Wholesale & retail | 2024 |
| Sisters Sharing Style Limited | Information & communication | 2024 |
| SJ Management and Logistics Ltd | Professional & scientific | 2017 |
| Skyline Firestopping Ltd | Construction | 2021 |
| SLS Entertainments Limited | Professional & scientific | 2017 |
| SM Henley Holdings Limited | Financial services | 2022 |
| Smarcomms Ltd | Administrative & support | 2016 |
| Smart Donkey Ltd | Information & communication | 2023 |
| Smartedge Manufacturing Ltd | Manufacturing | 1999 |
| Smarter Britain Limited | Professional & scientific | 2021 |
| Smiley Cafes Limited | Hospitality | 2016 |
| Smiling Vine LLP | | 2025 |
| SMS Design & Consultancy Limited | Professional & scientific | 2012 |
| Snoooze Limited | Wholesale & retail | 2018 |
| Snowdon Financial Limited | Financial services | 2002 |
| Social Graffiti Limited | Information & communication | 2016 |