| Santarossa Architecture Limited | Professional & scientific | 2005 |
| Sapphire Management Services Ltd | Administrative & support | 2003 |
| Sarah Hardy Confectionery Ltd | Manufacturing | 2016 |
| Sarala Limited | Information & communication | 2007 |
| SAY SO Rose Limited | Wholesale & retail | 2025 |
| Sbsniper Ltd | Professional & scientific | 2026 |
| Scaleshock Limited | Other services | 2025 |
| SCI Chateau DU Francport Ltd | Real estate | 2024 |
| Scientiag International Limited | Agriculture & fishing | 2019 |
| Scion Investments Ltd | Financial services | 2016 |
| Scooop Protein Ice Cream Ltd | Hospitality | 2024 |
| SDS Facilities Limited | Manufacturing | 2010 |
| Sean Cook Safety Services Limited | Professional & scientific | 2016 |
| Seaton Lane Healthcare Limited | Real estate | 2015 |
| Seaton Lane Loan Note Company Limited | Financial services | 2015 |
| Securecare Consultants Limited | Professional & scientific | 2024 |
| Seed Crunch Limited | Manufacturing | 2026 |
| Sensor Fire Limited | Construction | 2017 |
| Serendipity Care Ltd | Health & social care | 2024 |
| Sesamoid Consulting Limited | Information & communication | 2018 |
| Setsail Properties Limited | Real estate | 2002 |
| Sevenoaks MR Limited | Water & waste | 2025 |
| SGC Holdings Limited | Administrative & support | 2006 |
| SGC Training Services Ltd | Education | 2018 |
| SGP Installers Ltd | Construction | 2023 |
| Shalford Investments Limited | Real estate | 1990 |
| Sharp Management Consultancy Limited | Information & communication | 2000 |
| Sheehan Electrical Limited | Construction | 2012 |
| Shelby Power Limited | Wholesale & retail | 2018 |
| Shiraj Shimul Properties Limited | Real estate | 2020 |
| Shirt Displays UK Limited | Manufacturing | 2016 |
| SHK Finance Limited | Professional & scientific | 2012 |
| Shopbycode Ltd | Information & communication | 2020 |
| SI Belle Beauty - Beauty Salons Ltd | Other services | 2021 |
| Sible Cafe Ltd | Hospitality | 2026 |
| Sibyl Dynamics Ltd | Professional & scientific | 2025 |
| Sick to Death Ltd | Wholesale & retail | 2025 |
| Side EYE Films Ltd | Information & communication | 2024 |
| Signature Dog Training Ltd | Education | 2023 |
| Silent Reviewer Limited | Information & communication | 2023 |
| Silly Yaks Limited | Hospitality | 2006 |
| Silver Steps Day Care Limited | Health & social care | 2018 |
| Silverback Bronze Limited | Administrative & support | 2016 |
| Simply Healthcare Limited | Professional & scientific | 2021 |
| Simply Nails Limited | Other services | 1999 |
| Site Sealants (UK) Ltd | Construction | 2013 |
| SJB Investments Group Ltd | Financial services | 2025 |
| Skidby Construction Ltd | Professional & scientific | 2025 |
| Skyvey Ltd | Professional & scientific | 2020 |
| Slas Property Management Ltd | Real estate | 2021 |
| SLJ Carpentry & Construction Ltd | Construction | 2016 |
| Small Town Homes Limited | Real estate | 2018 |
| Smart Repair IT Ltd | Manufacturing | 2014 |
| Smco Consultants Ltd | Professional & scientific | 2025 |
| Smillie Scaffolding Ltd | Construction | 2016 |
| Smith and Scillitoe Limited | Construction | 1973 |
| Snowden Fenn Management Company Limited | Real estate | 2007 |
| Snowdonia Pumped Hydro Limited | Professional & scientific | 2013 |
| Socc Electrical Ltd | Manufacturing | 2019 |
| Socius Partners Limited | Administrative & support | 2025 |
| Solal Awards Limited | Administrative & support | 2023 |
| Solar for Schools Projects 1 Limited | Financial services | 2024 |
| Solar Options for Schools Limited | Information & communication | 2015 |
| Solarflare Ltd. | Manufacturing | 2006 |
| Solution Fitters Ltd | Construction | 2011 |
| Sophie Hannah Richardson Limited | Professional & scientific | 2017 |
| Sophrology for Life Ltd | Education | 2021 |
| South East GAS Ltd | Construction | 2013 |
| Sp&I Ltd | Construction | 2020 |
| Spartan Contracts Ltd | Construction | 2024 |
| Spellbound Communications Ltd | Professional & scientific | 2012 |
| Sphere Safety Services Limited | Professional & scientific | 2025 |
| Spice Bond Ltd | Hospitality | 2025 |
| Spicesotic Plants Limited | Wholesale & retail | 2022 |
| Spiffingcovers.Com Ltd | Information & communication | 2013 |
| Spindler Demolition Ltd | Construction | 2022 |
| Sportgrove Limited | Arts & recreation | 1996 |
| Sporting Game Birds Limited | Agriculture & fishing | 2021 |
| Spritely Tyres Limited | Wholesale & retail | 2024 |
| Spyro Media Ltd | Information & communication | 2025 |
| SQ12 Consultancy Ltd | Professional & scientific | 2023 |
| Square Mile Review Services Limited | Professional & scientific | 2012 |
| Squirrel Estates Ltd | Real estate | 2023 |
| SR Essex Ltd | Wholesale & retail | 2023 |
| SRG Rail Ltd | Construction | 2014 |
| Srinivasa Retreat Ltd | Education | 2020 |
| SRS Scaffolding Ltd | Construction | 2023 |
| ST Edmunds Close (MC) Limited | Real estate | 2018 |
| ST Laurence View Management Company Limited | Real estate | 2020 |
| ST Lawrence Transport Services Limited | Transport & logistics | 2010 |
| ST. Annard Developments Limited | Real estate | 2001 |
| ST. George Property Group Limited | Real estate | 2016 |
| ST. Lawrence Court Management Company Limited | Households | 1987 |
| Stable Carbon Limited | Administrative & support | 2023 |
| Stanfield Developments Limited | Construction | 1984 |
| Stanley Hall Limited | Arts & recreation | 2005 |
| Stanstead Hall Farms Ltd | Extraterritorial | 2023 |
| Starbright PR Ltd | Professional & scientific | 2016 |
| Starmedics Care Ltd | Health & social care | 2023 |
| Stature Accountants Ltd | Professional & scientific | 2021 |