| SJV Aesthetics Ltd | Other services | 2024 |
| SK Broadcast Services Limited | Information & communication | 2023 |
| SK Estate & Properties Limited | Real estate | 2019 |
| SK Technologies Limited | Information & communication | 2011 |
| SKC Services Ltd | Construction | 2018 |
| Skmax Films Limited | Information & communication | 2017 |
| SKS Investments International Ltd | Financial services | 2017 |
| SKX Communications Limited | Professional & scientific | 2026 |
| Sky Blue Immigration Services Limited | Professional & scientific | 2023 |
| SKY-PRO24/7 Pest Control Ltd | Administrative & support | 2025 |
| Skybridge Albion Limited | Wholesale & retail | 2011 |
| Skylarks Charity | Other services | 2012 |
| Slainte London Limited | Wholesale & retail | 2026 |
| Sleep Organic Limited | Wholesale & retail | 2017 |
| Slhg Ltd | Other services | 2021 |
| Slnr Traders Ltd | Transport & logistics | 2025 |
| Sloane Healthcare Limited | Health & social care | 2012 |
| SLP Creations Ltd | Hospitality | 2024 |
| Small Dog Supply Chain Services Ltd | Other services | 2019 |
| Small Island Films | Arts & recreation | 2006 |
| Small Person Productions Limited | Professional & scientific | 2017 |
| Smart Eatery Limited | Hospitality | 2025 |
| Smart Films Ltd | Information & communication | 2014 |
| Smartedj Business Solutions Limited | Professional & scientific | 2025 |
| Smarter Human Ltd | Information & communication | 2017 |
| Smile & Shop Ltd | Wholesale & retail | 2023 |
| Smile in Turkey Ltd | Professional & scientific | 2023 |
| Smith Baxter Limited | Professional & scientific | 1996 |
| Smith Baxter Property Consultants Ltd | Professional & scientific | 2018 |
| SML Property Development Ltd | Construction | 2024 |
| Smmg Ltd | Information & communication | 2017 |
| Smooth Space Construction Ltd | Construction | 2022 |
| Smooth Space Ltd | Construction | 2019 |
| SNA Logistics Ltd | Transport & logistics | 2019 |
| Snappin' Turtle Productions Limited | Information & communication | 2011 |
| Snomad SKI Ltd | Information & communication | 2023 |
| Snow Bang Ltd | Extraterritorial | 2016 |
| Snow White Drycleaners Ltd | Other services | 2012 |
| Snow-Wise Limited | Administrative & support | 2013 |
| Social Fuel Ltd | Professional & scientific | 2025 |
| Social Media SEO Limited | Professional & scientific | 2010 |
| Sofa Bespoke Ltd | Wholesale & retail | 2014 |
| Sofinish Technologies Limited | Information & communication | 2023 |
| Sohail Rizvi Limited | Health & social care | 2024 |
| Sohini Shah Consultancy Ltd | Financial services | 2018 |
| Soigne Interiors Limited | Wholesale & retail | 2021 |
| Sola Terra Records Ltd | Information & communication | 2017 |
| Solar Cloud Ltd | Construction | 2025 |
| Sole Starz Ltd | Wholesale & retail | 2021 |
| Solitlabs IT Solutions & Consultancy Services Ltd | Information & communication | 2016 |
| Soliton Resources Limited | Mining & quarrying | 2017 |
| Solomon Shop Ltd | Information & communication | 2021 |
| Solve for Growth Ltd | Professional & scientific | 2018 |
| Somermoor Estates Limited | Professional & scientific | 1987 |
| Somerset Business Park Limited | Real estate | 2022 |
| Sommers Creative Production Ltd | Information & communication | 2026 |
| Sommers Ltd | Information & communication | 2022 |
| Son's of Beeches Driveways & Patios Ltd | Administrative & support | 2025 |
| Sone Products Acquisition Limited | Financial services | 2025 |
| Sonit Ltd | Real estate | 2016 |
| Sophie Smith Productions Limited | Information & communication | 2016 |
| Sornaraj Investment Ltd | Real estate | 2018 |
| Sornaraj Private Ltd | Wholesale & retail | 2012 |
| Soulhub Limited | Information & communication | 2016 |
| Source Entertainment Ltd | Information & communication | 2024 |
| South Lodge Management Limited | Households | 1981 |
| Southcorp XUK Limited | Professional & scientific | 1988 |
| Southern Classics Car Storage Ltd | Administrative & support | 2011 |
| Southern Implants U.K. Limited | Wholesale & retail | 2005 |
| Southern Manufacturing Show Limited | Administrative & support | 1997 |
| Sovereign Assets Limited | Real estate | 2002 |
| Spaced OUT Events LLP | | 2018 |
| Spacextend Ltd | Construction | 2025 |
| Spantikgold Limited | Wholesale & retail | 2025 |
| Sparked Labs Ltd | Information & communication | 2026 |
| Sparkk Store Ltd | Wholesale & retail | 2024 |
| Sparkling Joy Limited | Real estate | 2024 |
| Sparks Ventures Limited | Real estate | 2026 |
| Spear Housing Association Limited | Health & social care | 2007 |
| Spearhead Piste Ltd | Financial services | 2024 |
| Special Media Ltd | Wholesale & retail | 2020 |
| Spectrum Roofing Ltd | Construction | 2019 |
| Spectrum Telecom Services Ltd | Information & communication | 1998 |
| Speedex Worldwide Express Limited | Transport & logistics | 2018 |
| Spencer Consulting Limited | Professional & scientific | 2022 |
| Sphere Luxe Ltd | Professional & scientific | 2018 |
| Spinwheel DRY Cleaners Ltd | Other services | 2024 |
| Spirodell Holdings Limited | Administrative & support | 2011 |
| Spjt Training Group Limited | Arts & recreation | 2026 |
| Sport Media Publications Limited | Information & communication | 2020 |
| Sportive Kids Ltd | Education | 2024 |
| Sports & Physiotherapy Ltd | Health & social care | 2016 |
| Spray Concept Ltd | Other services | 2019 |
| Sprig Gardens Ltd | Administrative & support | 2024 |
| Springboard Swimmers Ltd. | Arts & recreation | 2002 |
| Springly Health Ltd | Wholesale & retail | 2020 |
| SPS Financing Limited | Administrative & support | 2006 |
| Sqjr Ltd | Real estate | 2022 |
| Square Circle Properties Limited | Construction | 2020 |
| Square Circle Trading Limited | Administrative & support | 2016 |