| Sapiens Software Ltd | Information & communication | 2018 |
| Sauna LAB UK Ltd | Construction | 2024 |
| Saville Quinn UK Ltd | Wholesale & retail | 2021 |
| Saxon Subsea Ltd | Professional & scientific | 2018 |
| Sayah Consulting Limited | Transport & logistics | 2021 |
| Sayeen International Ltd | Information & communication | 2025 |
| SB Freight Ltd | Transport & logistics | 2021 |
| Sbgn Consultancy Limited | Construction | 2012 |
| Sbvn Ltd | Hospitality | 2026 |
| SC Electrical Contractors Ltd | Construction | 2010 |
| SC Scenery Limited | Information & communication | 2016 |
| Scene IT Scenic Ltd | Information & communication | 2022 |
| School Staff KIT Ltd | Wholesale & retail | 2024 |
| Scope T&M-Uk Ltd | Manufacturing | 2025 |
| Scrubs Lane Operating Company Ltd | Transport & logistics | 2023 |
| Scutum East Limited | Administrative & support | 2000 |
| Scutum London Limited | Public administration | 2000 |
| Scutum Property UK Limited | Real estate | 2017 |
| Scutum South East Limited | Administrative & support | 1975 |
| Scutum UK & Ireland Ltd | Construction | 2018 |
| SD Hussey Ltd | Information & communication | 2022 |
| Sdal Ltd | Manufacturing | 2019 |
| SDE Partners (UK) Limited | Professional & scientific | 2013 |
| SDL Tree and Landscaping Services Ltd | Administrative & support | 2026 |
| SDS Management Consulting Ltd | Professional & scientific | 2017 |
| SE7EN Developments Ltd | Construction | 2022 |
| Search Engine Optimisation Limited | Other services | 2015 |
| SEB Plumbing & Heating Ltd | Construction | 2023 |
| Second 2 None Fire Safety Ltd | Professional & scientific | 2025 |
| Securipad Ltd | Other services | 2023 |
| Seddon Consultancy Limited | Professional & scientific | 2015 |
| Self-Adhesive Supplies Limited | Extraterritorial | 1972 |
| Selfstore London Limited | Real estate | 2016 |
| Serge-Art Decoration Limited | Administrative & support | 2002 |
| Serious Energy Limited | Energy | 2023 |
| Serpentine Books Limited | Wholesale & retail | 2018 |
| Servechill AI & Data Transformation Limited | Information & communication | 2026 |
| Setera UK Limited | Information & communication | 2017 |
| Seven Star Holdings Limited | Real estate | 2022 |
| Sevita (UK) Limited | Administrative & support | 2008 |
| Seyon Investments Limited | Financial services | 2019 |
| Seyon Limited | Wholesale & retail | 2004 |
| SG Project Management Limited | Construction | 2003 |
| Sgss Investments Ltd | Real estate | 2024 |
| Shades Barbados Limited | Administrative & support | 2001 |
| Shahana Properties Ltd | Real estate | 2025 |
| Sharma Sons Limited | Real estate | 2021 |
| Sheet Plastics UK Limited | Wholesale & retail | 2022 |
| Sheoran & Co Limited | Real estate | 2023 |
| Sheridon IMS Limited | Professional & scientific | 2008 |
| Shins Ocean Delight Ltd | Hospitality | 2024 |
| Ship Lane Farnborough Ltd | Construction | 2024 |
| Shray & Co Supplies Limited | Wholesale & retail | 2024 |
| Sident Sales Ltd. | Health & social care | 1994 |
| Sident Technologies Limited | Information & communication | 2017 |
| Sident Technology Holdings Limited | Financial services | 2025 |
| SIG Industrial Gases Limited | Wholesale & retail | 2002 |
| Sigil IT Consultancy Ltd | Information & communication | 2021 |
| Signals at Scale Limited | Information & communication | 2026 |
| Signature Double Glazing Ltd | Construction | 2023 |
| Silverdale Windows and Doors Limited | Construction | 2018 |
| Silverland Stone Limited | Wholesale & retail | 1994 |
| Silvermoon Property Holdings Ltd | Real estate | 2025 |
| Silverwood Management Woking Limited | Professional & scientific | 1997 |
| Simba Motors Ltd | Wholesale & retail | 2024 |
| Simering Engineering (Shangai) Co Ltd | Wholesale & retail | 2024 |
| Simplify My Home Ltd | Construction | 2003 |
| Siow Dragon WOK Ltd | Hospitality | 2021 |
| Sirius Management Limited | Professional & scientific | 2003 |
| Sithco Solutions Ltd | Information & communication | 2018 |
| Sitra IT Services Limited | Information & communication | 2024 |
| Sixtystone Press Limited | Administrative & support | 2008 |
| SJD Ventures Limited | Professional & scientific | 2021 |
| SJM Real Estate Investment Limited | Real estate | 2024 |
| SJS Inc. Ltd | Professional & scientific | 2025 |
| Skeates Consultancy Ltd | Professional & scientific | 2026 |
| Skilled Careers Ltd | Information & communication | 2009 |
| Skin Graph Limited | Professional & scientific | 2012 |
| Skin Laboratory International Ltd | Wholesale & retail | 2017 |
| Skkz Properties Ltd | Real estate | 2020 |
| SKM Cleaning 2 Ltd | Administrative & support | 2025 |
| SKS Investors Limited | Real estate | 2020 |
| Skye Dental Hygienist Ltd | Health & social care | 2025 |
| Sleek Software Research and Solutions Ltd | Professional & scientific | 2011 |
| Sliding Wardrobe Warehouse Holdings Limited | Financial services | 2020 |
| Sm-Ink Finish Ltd | Financial services | 2023 |
| Smaart Management Ltd | Real estate | 2018 |
| Smandour Limited | Health & social care | 2023 |
| Smart Claimz Limited | Professional & scientific | 2025 |
| Smartfix Homes Ltd | Construction | 2025 |
| Smgu Limited | Administrative & support | 2016 |
| Smile Homes Ltd | Real estate | 2026 |
| Smythe-Wood's Ltd | Water & waste | 2022 |
| Snag and Surv Ltd | Professional & scientific | 2024 |
| Snowhill Advisory Limited | Administrative & support | 2014 |
| SO Sinatra Limited | Arts & recreation | 2014 |
| Social Park Housing Limited | Professional & scientific | 2018 |
| Soiree Events Surrey Limited | Administrative & support | 2016 |
| Solar-Charge Limited | Energy | 2022 |
| Solares Ltd | Construction | 2014 |