| SAS (Safety at Scale) Limited | Administrative & support | 2022 |
| SAS Fleetcare Ltd | Wholesale & retail | 2021 |
| Saskia Designs Limited | Wholesale & retail | 2008 |
| Sasquash UK Limited | Wholesale & retail | 2018 |
| SAT Visuals Limited | Wholesale & retail | 2021 |
| Satom Housing Consultancy Ltd | Health & social care | 2021 |
| Sats Security Services Limited | Administrative & support | 2010 |
| Savageknight Management Ltd | Real estate | 2025 |
| Saxon Security Services Ltd | Other services | 2016 |
| Saylus UK Ltd | Professional & scientific | 2024 |
| SB Financial Consulting Limited | Professional & scientific | 2017 |
| SB Plumbing (Kent) Limited | Construction | 2017 |
| Sbr-Sha Limited | Health & social care | 2015 |
| SBS Consultants Global Limited | Information & communication | 2016 |
| SCA Logistics Ltd | Professional & scientific | 2023 |
| Scaffix Ltd | Construction | 2025 |
| Scaffsubs Ltd | Construction | 2021 |
| Scancom UK Limited | Wholesale & retail | 2000 |
| SCC Doherty Ltd | Health & social care | 2021 |
| School Time Ltd | Wholesale & retail | 2021 |
| Schunk Consulting Limited | Professional & scientific | 2025 |
| SCM Plumbing & Heating Ltd | Construction | 2017 |
| SCM Ventures Limited | Professional & scientific | 2024 |
| SCO Consulting Ltd | Professional & scientific | 2025 |
| Scolly Luxury Drink Limited | Wholesale & retail | 2025 |
| SCORPION78 Ltd | Transport & logistics | 2019 |
| Screach Property Limited | Real estate | 2015 |
| Screed Bound Services Ltd | Construction | 2026 |
| Scribes Engineering Services Ltd | Professional & scientific | 2014 |
| SDA Packaging Limited | Manufacturing | 2005 |
| SDM Training Services Limited | Education | 2021 |
| Sdsjca Property Limited | Real estate | 2025 |
| SDT Accounting and Taxation Services Limited | Professional & scientific | 1999 |
| SDT Properties (Barbados) Limited | Real estate | 2020 |
| SDT Properties 2017 Limited | Real estate | 2017 |
| SDT Properties Limited | Real estate | 2003 |
| Sea Shells Nursery (Dockside) Limited | Health & social care | 2017 |
| Sea Shells Nursery Limited | Health & social care | 2017 |
| Seafood Products Limited | Wholesale & retail | 1987 |
| Seafood Souq UK Ltd | Wholesale & retail | 2023 |
| Sebi&Ionut Trans Ltd | Transport & logistics | 2022 |
| Sebion Ltd | Construction | 2020 |
| Second Nature First AID Limited | Administrative & support | 2025 |
| Secondside Ltd | Administrative & support | 2025 |
| Security & Electrical Group Ltd | Construction | 2025 |
| Security Force Management Ltd | Administrative & support | 2006 |
| SED Aquatics Ltd | Wholesale & retail | 2023 |
| Sedalux Ltd | Professional & scientific | 2017 |
| SEE and Create CIC | Education | 2022 |
| SEE the Word Limited | Manufacturing | 2000 |
| Seed Analytics Ltd | Information & communication | 2021 |
| Seed Services Ltd | Financial services | 2020 |
| Seeonix Ltd | Wholesale & retail | 2023 |
| Seetrue Cleaning Services Ltd | Administrative & support | 2026 |
| Segas Sailing Club | Arts & recreation | 1997 |
| Sekhmet Properties Ltd | Real estate | 2022 |
| Sekvoia Ltd | Transport & logistics | 2021 |
| Seld Property UK Ltd | Real estate | 2024 |
| Select Infrastructure Limited | Construction | 2008 |
| Selection Stores Limited | Wholesale & retail | 2008 |
| SEN Voice Ltd | Professional & scientific | 2025 |
| Sensitive Sound Ltd | Administrative & support | 1999 |
| Sensory Balance Limited | Health & social care | 2024 |
| Senworb Ltd | Real estate | 2024 |
| Sepro Mineral Processing International Limited | Manufacturing | 2004 |
| Serena Louise Ltd | Wholesale & retail | 2025 |
| Serenity Care Solutions Ltd | Health & social care | 2023 |
| Sergio Cardoso Ltd | Construction | 2026 |
| Seria Limited | Transport & logistics | 2003 |
| Serra.Io Ltd | Information & communication | 2024 |
| Service Pro Limited | Construction | 2016 |
| SET2 Secure Limited | Arts & recreation | 2026 |
| Setterfield Limited | Construction | 2022 |
| Settle for Safety Limited | Administrative & support | 2007 |
| Sevara Living Ltd | Real estate | 2025 |
| Seven Cities Limited | Real estate | 2020 |
| SFD Solutions Limited | Professional & scientific | 2018 |
| SFI Homes Ltd | Real estate | 2024 |
| SFM3 Ltd | Construction | 2021 |
| SFS Project Management Ltd | Construction | 2015 |
| SG Boiler Care Ltd | Construction | 2025 |
| SGD Solutions Limited | Construction | 2020 |
| SGM Healthcare Consulting Limited | Information & communication | 2025 |
| SGT. Scuffs Ltd | Wholesale & retail | 2023 |
| SHA TIN Consulting Limited | Information & communication | 1995 |
| Shabaq Ltd | Wholesale & retail | 2025 |
| Shadyat Healthcare Services Limited | Health & social care | 2024 |
| Shahmeer Moon Ltd | Wholesale & retail | 2026 |
| Shalom Medical Services Limited | Health & social care | 2023 |
| Shams Consulting Ltd | Professional & scientific | 2025 |
| Shane Coventry Ltd | Construction | 2025 |
| Shannon House RTM Company Ltd | Households | 2025 |
| Shanti 13 Limited | Real estate | 2019 |
| Share a Chauffeur Limited | Transport & logistics | 2025 |
| Shared Family Circles Ltd | Education | 2018 |
| Shared Roots Ltd | Real estate | 2025 |
| Shark Esms Limited | Administrative & support | 2019 |
| Sharleigh Ltd | Administrative & support | 2019 |
| Sharon Ellis Consultancy Ltd | Education | 2021 |
| Sharp & Owen Hair Salon Ltd | Other services | 2016 |