| Sasse Facilities Management Limited | Administrative & support | 2003 |
| Sasse Limited | Administrative & support | 2010 |
| Sassy Glow Ltd | Other services | 2018 |
| Satargo UK Limited | Wholesale & retail | 2021 |
| Satchi Accountancy Services Ltd | Professional & scientific | 2017 |
| Satchi UK Ltd | Professional & scientific | 2003 |
| Satcon Limited | Information & communication | 2012 |
| Sateridevi Limited | Real estate | 2025 |
| Saturn Crystals London Ltd | Wholesale & retail | 2018 |
| Saunders Carpentry and Building Ltd | Construction | 2022 |
| Saunders Tech Ltd | Information & communication | 2021 |
| Saunderton Ltd | Administrative & support | 2025 |
| Saunderton Secretarial Services Limited | Extraterritorial | 1996 |
| Saunderton Vale Management Company Limited | Households | 1994 |
| Save My Tax Ltd | Professional & scientific | 2012 |
| Save My Taxes Ltd | Administrative & support | 2022 |
| Save on Packaging Ltd | Wholesale & retail | 2023 |
| Saved by the Ball Coaching Ltd | Education | 2023 |
| Saveur UK One Limited | Real estate | 2022 |
| Savi Auto Solutions Limited | Wholesale & retail | 2017 |
| Savile ROW Visiting Tailors Limited | Wholesale & retail | 2004 |
| Saving Agents Ltd | Professional & scientific | 2026 |
| Savvy Hospitality Ltd | Wholesale & retail | 2012 |
| Sawbones Europe A.B | | 1986 |
| Sawhney Medical Ltd | Health & social care | 2012 |
| Saxi Limited | Wholesale & retail | 2024 |
| Saxon Park Management Company Limited | Extraterritorial | 2005 |
| Saxon Property Management Limited | Real estate | 1992 |
| Sayarti Ltd | Wholesale & retail | 2020 |
| SB Connexions Ltd | Information & communication | 2025 |
| SB Enterprizes Ltd | Information & communication | 2018 |
| SB Fruit & VEG Ltd | Wholesale & retail | 2017 |
| Sbcom Ltd | Construction | 2019 |
| SBM Glazing Ltd | Manufacturing | 2019 |
| SBW Designs Ltd | Construction | 2014 |
| SBX Limited | Transport & logistics | 2018 |
| SC Property Solutions Limited | Real estate | 2021 |
| Scaffold Savvy Ltd | Construction | 2025 |
| Scaffoldmaster Hire Limited | Administrative & support | 2025 |
| Scale Liverpool Ltd | Real estate | 2021 |
| Scale Music and Sound Hits Limited | Information & communication | 1978 |
| Scaleseries Ltd | Information & communication | 2026 |
| Scaleup Street Limited | Information & communication | 2017 |
| Scalewavesol Ltd | Wholesale & retail | 2026 |
| Scaling Trade Ltd | Professional & scientific | 2025 |
| Scanbac Ltd | Information & communication | 2025 |
| Scandia Care Limited | Real estate | 2007 |
| Scarlet Group Limited | Transport & logistics | 2001 |
| Scented Breezes Ltd | Wholesale & retail | 2025 |
| Scevity & Co Limited | Professional & scientific | 2014 |
| Scholar & Story Ltd | Professional & scientific | 2024 |
| Scholars Place (Gerrards Cross) Management Company Limited | Households | 2015 |
| Scholtke &Co. Ltd | Professional & scientific | 2000 |
| Schultz & Larsen Ltd | Wholesale & retail | 2015 |
| Sciaky Electric Welding Machines Limited | Manufacturing | 1934 |
| Sciaky Electronics Limited | Manufacturing | 2001 |
| Scissor Paper Stone Limited | Information & communication | 2008 |
| SCL Publishing Ltd | Information & communication | 2024 |
| Scorpios Brewary Ltd | Hospitality | 2018 |
| Scott Healthcare Limited | Public administration | 2021 |
| Scott Mode Ltd | Wholesale & retail | 2026 |
| Scott's Elite Landscapes Limited | Administrative & support | 2019 |
| Scotts Roofing Ltd | Construction | 2010 |
| Scottwood Homes (UK) Limited | Construction | 2003 |
| Scottwood Long Acre Limited | Construction | 2004 |
| SCR Real Estate Ltd | Real estate | 2012 |
| Screen Interiors Ltd | Professional & scientific | 2014 |
| SCT Team Ltd | Construction | 2019 |
| SD Sporthorses Limited | Wholesale & retail | 2012 |
| SD Tech. Ltd | Wholesale & retail | 2025 |
| SDB Tiling Limited | Construction | 2006 |
| Sdicc Services Limited | Administrative & support | 2025 |
| Sdmit Solutions Ltd | Information & communication | 2024 |
| Sea G Limited | Other services | 2021 |
| Sea Moss Naturals Ltd | Manufacturing | 2021 |
| Seal Advisors Ltd | Professional & scientific | 2013 |
| Seal's Cove Shooting Ground Ltd | Arts & recreation | 2024 |
| Sealright Limited | Construction | 2018 |
| Seamelav Estates Limited | Real estate | 2018 |
| Seamelav Limited | Professional & scientific | 2016 |
| Seamless Technology Solutions Limited | Professional & scientific | 2022 |
| Sean Mchugh Limited | Information & communication | 2011 |
| Search Fire and Security Limited | Administrative & support | 2023 |
| Seat Belts Solutions Ltd | Wholesale & retail | 2021 |
| Seaward Security Ltd | Construction | 2003 |
| Sebrat Limited | Health & social care | 2016 |
| Secet Limited | Professional & scientific | 2000 |
| Seciq Ltd | Information & communication | 2025 |
| Second User Furniture Limited | Wholesale & retail | 2019 |
| Secret of Pilates Limited | Arts & recreation | 2020 |
| Secure Medical Services Ltd | Transport & logistics | 2022 |
| Secure Soft IT Ltd | Information & communication | 2024 |
| Secure Your Home Limited | Administrative & support | 2011 |
| Secured Hands Properties Limited | Real estate | 2023 |
| Securerole Ltd | Administrative & support | 2024 |
| Sed&A Ltd | Manufacturing | 2023 |
| Sedel Capital LLP | | 2009 |
| SEE Educational Experiences Ltd | Education | 2026 |
| SEE Marketing Solutions Limited | Extraterritorial | 2007 |
| SEE YOU Next Thursday LLP | | 2008 |