| Second Opinion Experts Alliance Limited | Other services | 2013 |
| Secondshelf Ltd | Information & communication | 2026 |
| Sector Services Suppliers Ltd | Wholesale & retail | 2014 |
| Sectus Ltd | Professional & scientific | 2016 |
| Secured Properties Limited | Construction | 2007 |
| Sedbury Property Limited | Real estate | 2001 |
| Sedomaris Limited | Professional & scientific | 2015 |
| Seek Dharma Limited | Administrative & support | 2021 |
| Seemee London Limited | Manufacturing | 2016 |
| Seheno Services Limited | Hospitality | 2025 |
| Selenity Limited | Information & communication | 1989 |
| Selwyn Capital Ltd | Professional & scientific | 2018 |
| Sempera Partners LLP | | 2015 |
| Sempre Analytics Limited | Information & communication | 2011 |
| Sentio Property Solutions Ltd | Construction | 2021 |
| September Twenty Two Limited | Wholesale & retail | 2019 |
| Septon Co. Ltd | Professional & scientific | 2018 |
| Seraph Cerulean Ltd | Professional & scientific | 2025 |
| Seroxo Limited | Health & social care | 2020 |
| Serpent Films Limited | Information & communication | 2005 |
| Sertsari Private Training Studio Ltd | Wholesale & retail | 2020 |
| Seru Traffic Ltd | Construction | 2022 |
| Serv Recruitment Ltd | Administrative & support | 2020 |
| Server Xeye Ltd | Information & communication | 2026 |
| Setanta Books Limited | Wholesale & retail | 2017 |
| Setanta Songs Limited | Information & communication | 2004 |
| Seva Service Ltd | Health & social care | 2011 |
| Sevco 5088 Limited | Arts & recreation | 2012 |
| Seven Capital Markets Ltd | Wholesale & retail | 2023 |
| Seven Dials Studios Limited | Information & communication | 2009 |
| Seven Sportswear Limited | Wholesale & retail | 2018 |
| Sewer Intelligence Ltd | Water & waste | 2020 |
| Seyf Dental Ltd | Extraterritorial | 2023 |
| Seyon Technologies Limited | Information & communication | 2011 |
| SF Factual Ltd | Information & communication | 2025 |
| SG Lawn Care Ltd | Administrative & support | 2024 |
| SG Physical Therapy Ltd | Other services | 2014 |
| Sh-Talent Ltd | Administrative & support | 2025 |
| Shaefer PR & Marketing Ltd | Professional & scientific | 2010 |
| Shainice Services Limited | Construction | 2025 |
| Shakespeare Residential (Orchard Road) Limited | Households | 2014 |
| Shakespeare Terrace (Headlease) Ltd | Real estate | 2012 |
| Shamdasani Publishing Services Ltd | Information & communication | 2013 |
| Shape Hair Design Limited | Other services | 2013 |
| Sharon Eyre & Co. Ltd | Professional & scientific | 2026 |
| Sharp Business Insights Limited | Professional & scientific | 2013 |
| Sharpe Properties (QW) Ltd | Real estate | 2021 |
| Sharper Developments Limited | Real estate | 2018 |
| Sharper Property Management Limited | Real estate | 2024 |
| Shaun Ashton Design Ltd | Manufacturing | 2014 |
| Shave Ltd | Wholesale & retail | 2017 |
| Shaw and Company (Surveyors) Limited | Extraterritorial | 1997 |
| Shaw Porter Limited | Professional & scientific | 1973 |
| SHB Collective Ltd | Health & social care | 2026 |
| SHE Rises Resort Ltd | Manufacturing | 2017 |
| Shearwater Geophysical Company Limited | Professional & scientific | 2005 |
| Shed Light Consulting Ltd | Professional & scientific | 2024 |
| Sheen Court Limited | Households | 1976 |
| Sheen Park Management Limited | Households | 1990 |
| Sheen Wines Ltd | Wholesale & retail | 2019 |
| Sheerline Holdings Ltd | Professional & scientific | 2021 |
| Sheffield Assured Tenancies Limited | Real estate | 1988 |
| Sheldon & Wood Roofing & Property Maintenance Limited | Construction | 2024 |
| Shelfie AI Ltd | Information & communication | 2022 |
| Shepherd Helmets Ltd | Wholesale & retail | 2025 |
| Sherbrooke Consulting Limited | Professional & scientific | 2018 |
| Sherwood Limited | Professional & scientific | 2008 |
| Sherwood Power Limited | Energy | 2024 |
| Shine Investments Limited | Real estate | 1956 |
| Shine Two Limited | Other services | 2011 |
| Shineverse Ltd. | Financial services | 2023 |
| Shinsei Investments | Professional & scientific | 2022 |
| Shire Country Services LLP | | 2011 |
| Shiv Properties UK Ltd | Real estate | 2017 |
| Shmilly Ltd | Wholesale & retail | 2026 |
| Shoe Loops Ltd | Wholesale & retail | 2022 |
| Shopasa Ltd | Wholesale & retail | 2026 |
| Shore Furse Ltd | Hospitality | 2024 |
| Shoreline Engineering Solutions Ltd | Professional & scientific | 2019 |
| Shoreline INK Ltd | Information & communication | 2024 |
| Shoreline Property Solutions Ltd | Construction | 2019 |
| Shotbox Productions Limited | Other services | 2006 |
| Shottery Brook Management Company (NO.1) Limited | Households | 2003 |
| Shottery Brook Management Company (NO.2) Limited | Households | 2005 |
| Show Studio Limited | Wholesale & retail | 2000 |
| Show UK Limited | Professional & scientific | 1999 |
| Showstudio Productions Limited | Information & communication | 2002 |
| Shropshire Hotel Limited | Hospitality | 2009 |
| Shutter Blinds London Ltd | Manufacturing | 2025 |
| SI Belle Beauty Salon Ltd | Other services | 2019 |
| Side Hustle (O.M) Ltd | Real estate | 2019 |
| Sidontree Limited | Households | 1981 |
| Silk Email Ltd | Professional & scientific | 2017 |
| Silk Marketing Global Ltd | Financial services | 2025 |
| Silkroot Trading Company Limited | Health & social care | 2000 |
| Silver EGG Solutions Limited | Information & communication | 2013 |
| Silverdale Seaview Holidays Ltd | Hospitality | 2021 |
| Silverwings Group Limited | Extraterritorial | 2012 |
| Silverwood GDS Pharma Industry and Trade Ltd | Information & communication | 2022 |
| Simindex Ltd | Information & communication | 2026 |