| Safety-Kleen U.K. Limited | Manufacturing | 1974 |
| Safetykleen Finance Limited | Professional & scientific | 2008 |
| Safetykleen Group Services Limited | Professional & scientific | 2008 |
| Saffron Rage (Investments) Ltd | Real estate | 2017 |
| Saga Pro Limited | Construction | 2021 |
| Saggu Properties Limited | Real estate | 2023 |
| Sagous Limited | Information & communication | 2021 |
| Sagrahi Limited | Wholesale & retail | 2019 |
| Saharacity Take Away Limited | Hospitality | 2025 |
| Saies London Limited | Wholesale & retail | 2025 |
| Sainetor Solutions UK Limited | Information & communication | 2018 |
| Saintley Services Limited | Wholesale & retail | 2025 |
| Salley Limited | Real estate | 2012 |
| Sally Jamal Limited | Construction | 2024 |
| Salo Investments Limited | Real estate | 2026 |
| SAM BAO Consultancy Ltd | Administrative & support | 2024 |
| SAM Butters Productions Ltd | Arts & recreation | 2025 |
| SAM K Creative Ltd | Professional & scientific | 2018 |
| SAM Management Property Ltd | Transport & logistics | 2010 |
| Sam's Property Ltd | Real estate | 2019 |
| Samaya Ventures Limited | Administrative & support | 2013 |
| Sambosa Catering & Services Ltd | Hospitality | 2024 |
| Samo Coffee and Desert Ltd | Hospitality | 2019 |
| Samritz Healthcare Ltd | Manufacturing | 2013 |
| Samruddhi IT Consulting Ltd | Information & communication | 2024 |
| Samsung Bioepis UK Limited | Administrative & support | 2014 |
| Samsung C&T U.K. Limited | Wholesale & retail | 1975 |
| Samuel Hawthorne Limited | Real estate | 2023 |
| Sanges Ltd | Wholesale & retail | 2023 |
| Sansha Global Ltd | Wholesale & retail | 2025 |
| Santerino Management Ltd | Manufacturing | 2019 |
| Santhosh Decoration Ltd | Other services | 2018 |
| Santoshi Consulting Limited | Professional & scientific | 2026 |
| Sanzen Digital Marketing Limited | Professional & scientific | 2016 |
| Saoirse's Adventures Ltd | Administrative & support | 2026 |
| Sapra Property Ltd | Real estate | 2023 |
| Saramel Limited | Wholesale & retail | 2023 |
| Sardari Holdings Ltd | Real estate | 2024 |
| Satlance Entertainment Ltd | Information & communication | 2025 |
| Satlance Industries Ltd | Professional & scientific | 2024 |
| Savdel Limited | Health & social care | 2013 |
| SAW Building Services Ltd | Construction | 2011 |
| Sayhan Patwary Limited | Real estate | 2023 |
| SB Hospitality Limited | Hospitality | 2020 |
| SB TW8 Limited | Hospitality | 2026 |
| Scalens Studio Ltd | Information & communication | 2019 |
| SCE Director Ltd | Wholesale & retail | 2018 |
| Scene 852 Productions UK Limited | Information & communication | 2022 |
| Scentory Ltd | Manufacturing | 2025 |
| Schimper Digital Ltd | Information & communication | 2020 |
| Schools Counselling Partnership Limited | Health & social care | 2015 |
| Schrevs Limited | Education | 2017 |
| Scient Tech Limited | Information & communication | 2022 |
| Scient Technologies Limited | Information & communication | 2022 |
| Scoil Rince Ceim OIR Limited | Administrative & support | 2003 |
| SD Global Ventures Ltd | Wholesale & retail | 2024 |
| SDA Business Solutions Ltd | Administrative & support | 2022 |
| Sea N Sky Limited | Wholesale & retail | 2019 |
| Seager & Goard Limited | Construction | 2025 |
| Sealumet Europe Limited | Manufacturing | 2013 |
| Seans CG Limited | Financial services | 2025 |
| Seans Dance Limited | Arts & recreation | 2020 |
| Seans London Property Group Ltd | Construction | 2021 |
| Search and Stuff Ltd | Professional & scientific | 2024 |
| Seaside (UK) Trading Ltd | Wholesale & retail | 2013 |
| Seatech Limited | Financial services | 2007 |
| Second Nature (Holdings) Limited | Professional & scientific | 2009 |
| Second Nature Limited | Manufacturing | 1981 |
| Second Nature Publishing Limited | Administrative & support | 2009 |
| Secretcto Limited | Information & communication | 2019 |
| Sector 4 Focus Limited | Administrative & support | 2010 |
| Secureguard Services Limited | Administrative & support | 2021 |
| Seestep Ltd | Professional & scientific | 2015 |
| Sekason Global Ltd | Wholesale & retail | 2018 |
| Sekason Research Ltd | Information & communication | 2022 |
| Sekla Ltd | Professional & scientific | 2024 |
| Self Sustaining Properties Limited | Real estate | 2008 |
| Sell Practice Limited | Professional & scientific | 2026 |
| SEN Educate Limited | Administrative & support | 2025 |
| Senacare Services Limited | Health & social care | 2019 |
| Senan Ltd | Real estate | 2020 |
| Senior Property Advisory Limited | Construction | 2018 |
| Senior Property Associates Limited | Construction | 2018 |
| Senior Property Limited | Construction | 2019 |
| Sera Homes Ltd | Construction | 2019 |
| Serasky Ltd | Wholesale & retail | 2026 |
| Serek E&M Solution Ltd | Construction | 2026 |
| Seren Ventures Ltd | Wholesale & retail | 2026 |
| Serendib Fuels Ltd | Wholesale & retail | 2012 |
| Serenity 9 Limited | Information & communication | 2009 |
| Seskin Consulting Limited | Professional & scientific | 2026 |
| Seven 23 Consulting Ltd | Administrative & support | 2024 |
| Sevt Ltd | Health & social care | 2009 |
| SF Cars Ltd | Wholesale & retail | 2022 |
| Sgdp Design Ltd | Professional & scientific | 2017 |
| Sgsecuris Limited | Administrative & support | 2023 |
| Shades of Haya Ltd | Professional & scientific | 2023 |
| Shadlink Limited | Administrative & support | 2009 |
| Shahada SAP Consultancy Ltd | Information & communication | 2019 |
| Shamehr Ltd | Health & social care | 2022 |