| Satacha Limited | Health & social care | 2013 |
| Satkunam Enterprise Limited | Wholesale & retail | 2018 |
| Saulid Works Ltd | Construction | 2024 |
| Sav&Dud Building Ltd | Construction | 2019 |
| Sav's Cafe Ltd | Hospitality | 2019 |
| Savage Mechanical Services Ltd | Construction | 2024 |
| Savoy Rentals Ltd | Real estate | 2024 |
| Sawdust and Ember Ltd | Manufacturing | 2022 |
| Sawyer Holdings Limited | Financial services | 2005 |
| Saxon Park NO. 4 Residents Company Limited | Households | 1989 |
| Sayisaran Ltd | Wholesale & retail | 2023 |
| Sayran Ltd | Wholesale & retail | 2025 |
| SAZ Consultancy Services Ltd | Health & social care | 2019 |
| Sazzad & Co Limited | Professional & scientific | 2026 |
| SB Barbers 88 Ltd | Other services | 2025 |
| SB Legal Marketing Ltd | Professional & scientific | 2023 |
| SB Mechanical Ltd | Construction | 2026 |
| SB Sark Ltd | Other services | 2019 |
| SB Truck Repairs Limited | Transport & logistics | 2024 |
| Sban Property Management Ltd | Households | 2025 |
| SBE Kent Limited | Construction | 2010 |
| SBH Investment Ltd | Real estate | 2024 |
| SBT Estates Limited | Real estate | 2023 |
| SC Heating Ltd | Construction | 2018 |
| SC Housing Solutions Ltd | Real estate | 2024 |
| Scale Service Ltd | Real estate | 2024 |
| Scallywags Grooming LLP | | 2024 |
| Scape (Whitstable) Management Company Limited | Households | 2015 |
| Scarlett James Limited | Other services | 2011 |
| Scent Reminiscent Limited | Wholesale & retail | 2012 |
| Schofield Contractors Limited | Administrative & support | 2013 |
| Schofield Couriers Limited | Transport & logistics | 2022 |
| School of Science Ltd | Education | 2012 |
| Scientifiq Ltd | Administrative & support | 2019 |
| SCJ Roofing Solutions Ltd | Construction | 2014 |
| Scorpion Press (London) Ltd | Manufacturing | 2003 |
| Scott Family Funerals Limited | Other services | 2024 |
| Scottshop Ltd | Wholesale & retail | 2026 |
| SCR Support Services Ltd | Construction | 2021 |
| Scream Room Film Limited | Professional & scientific | 2015 |
| Scribe Carpentry & Installations Ltd | Construction | 2009 |
| Scripictural Limited | Information & communication | 2024 |
| Sctl Facilities Ltd | Extraterritorial | 2024 |
| Sctl Plant Hire & Sales Ltd | Extraterritorial | 2024 |
| Sctl Trading Co Ltd | Construction | 2023 |
| Sculpt Event Group Ltd | Professional & scientific | 2026 |
| Sculpted by CAM Limited | Arts & recreation | 2025 |
| SD & JD Property Ltd | Real estate | 2017 |
| SD Ceilings Ltd | Construction | 2025 |
| SD London Food Limited | Hospitality | 2014 |
| SD Private Ltd. | Wholesale & retail | 2023 |
| SDM Sales Limited | Wholesale & retail | 2012 |
| Sdmm Fixers Tiles & Stone Ltd | Construction | 2025 |
| SDW Carpentry Limited | Construction | 2014 |
| SE ME Services Limited | Construction | 2023 |
| SE7 Holding Limited | Hospitality | 2024 |
| SE7 Traders Ltd | Other services | 2025 |
| SE9 Professional Services Ltd | Professional & scientific | 2020 |
| Sea Air Studio Ltd | Professional & scientific | 2025 |
| Sea Air Works Ltd | Financial services | 2025 |
| Sea Clean Limited | Manufacturing | 2023 |
| Sea Reach Systems Limited | Other services | 2013 |
| Sea Spares Ltd | Wholesale & retail | 2024 |
| Seal Facilities Management Ltd. | Other services | 2020 |
| Sealtite Glass Limited | Manufacturing | 1994 |
| Sealtite Group Limited | Manufacturing | 2000 |
| Sealtite Windows Limited | Manufacturing | 1986 |
| Searley's Toys Ltd | Wholesale & retail | 2024 |
| Seas Group (Essex) Ltd | Financial services | 2024 |
| Seas Group Ltd | Financial services | 2024 |
| Seas Management Ltd | Administrative & support | 2024 |
| Seas Operations Ltd | Administrative & support | 2024 |
| Secret Gems Property Limited | Real estate | 2019 |
| Secret Knowledge Limited | Administrative & support | 2012 |
| Secure Cargo Assured Limited | Transport & logistics | 1994 |
| Secure Electronic Applications Limited | Construction | 1999 |
| Secure IMD Limited | Information & communication | 2021 |
| SECURE27 UK Ltd | Administrative & support | 2019 |
| Secured Openings Ltd | Manufacturing | 1997 |
| Securevision Security Solutions Ltd | Administrative & support | 2026 |
| Securion Fire & Security Ltd | Administrative & support | 2025 |
| Security Systems Design Limited | Administrative & support | 2003 |
| SEDIR38 Limited | Real estate | 2022 |
| SEE (International) Property Ltd | Real estate | 2022 |
| Seecubic UK Limited | Information & communication | 2018 |
| Seedco Properties Ltd | Real estate | 2025 |
| Seena Holdings Ltd | Other services | 2022 |
| Seescape Limited | Administrative & support | 2001 |
| SEJ Automotives Limited | Wholesale & retail | 2026 |
| Select Leisure Purchasing Limited | Administrative & support | 1988 |
| Select Plant Hire Company Limited | Construction | 1985 |
| Selkent Estates Ltd | Real estate | 2024 |
| Selkent Property Company Limited | Real estate | 2022 |
| Selkent Surveyors Limited | Professional & scientific | 2018 |
| SEM Limited | Manufacturing | 1914 |
| Sema Mann Atelier Ltd | Manufacturing | 2018 |
| SEN SUPPLIES4U Ltd | Wholesale & retail | 2023 |
| Senap Ltd | Wholesale & retail | 2009 |
| Senderful CIC | Education | 2023 |
| Senex UK PVT Ltd | Manufacturing | 2013 |