| SA Invest Ltd | Arts & recreation | 2019 |
| Saffron Self Storage Limited | Transport & logistics | 2017 |
| Samnet Limited | Information & communication | 2009 |
| Sandero Digital Ltd | Wholesale & retail | 2016 |
| Santfer Innovation Limited | Wholesale & retail | 2024 |
| Sapientia Innovation Limited | Construction | 2025 |
| Sapphire Rock Limited | Professional & scientific | 2021 |
| Sarah James Productions Limited | Information & communication | 2011 |
| Sarah Oliver Photography Ltd | Professional & scientific | 2021 |
| Sarah Young Aesthetics Ltd | Other services | 2018 |
| Sarus Group Limited | Wholesale & retail | 2025 |
| Sarvasva Limited | Wholesale & retail | 2024 |
| Satin Aesthetics Ltd | Other services | 2023 |
| SB Panda Consulting Limited | Administrative & support | 2026 |
| SC Shaw Designs Ltd | Professional & scientific | 2018 |
| Scarem Limited | Manufacturing | 2008 |
| Schengen Visa Consultants Limited | Administrative & support | 2026 |
| Scopesync Limited | Real estate | 1999 |
| Scott & Goose LLP | | 2014 |
| Scott Walker Auto 2000 Limited | Wholesale & retail | 2025 |
| Scott-Barden Multi-Trade Limited | Manufacturing | 2016 |
| Screen Time Ltd | Manufacturing | 2025 |
| Scrubbs Lane FSC Ltd | Real estate | 2019 |
| SCT Propco Ltd | Construction | 2025 |
| Sd&Cc Entertainment Ltd | Wholesale & retail | 2025 |
| Sda-Installations Ltd | Construction | 2019 |
| Seabourne Holdings Limited | Professional & scientific | 1962 |
| Seashell Care Limited | Health & social care | 2020 |
| SECNET/KARLHENDERSON77 Limited | Information & communication | 2018 |
| Second Fortis Green Properties(Management) Limited | Real estate | 1968 |
| Secure Shredding & Destruction Ltd | Water & waste | 2025 |
| Seed Space 1 Limited | Administrative & support | 2021 |
| Seed Space 2 Limited | Real estate | 2022 |
| Seed Space Group Limited | Administrative & support | 2020 |
| Self Obsessed Ltd | Wholesale & retail | 2019 |
| Selma Suna Eren Ltd | Hospitality | 2024 |
| SER Contractor Ltd | Construction | 2010 |
| SER Holdings Ltd | Financial services | 2017 |
| SER Homes Ltd | Construction | 2017 |
| SER Real Estate Ltd | Real estate | 2023 |
| SER Windows & Doors Ltd | Construction | 2019 |
| Serendipity Networks Limited | Information & communication | 2025 |
| Seres Information Technologie Ltd | Information & communication | 2012 |
| Serta Technologies Ltd | Information & communication | 2015 |
| Service in Motion Limited | Manufacturing | 2002 |
| Serviceable Limited | Construction | 2021 |
| Seven Hells Ltd | Information & communication | 2024 |
| SF Build London Limited | Construction | 2025 |
| Sfgrouplondon Ltd | Real estate | 2025 |
| SFS Group London Ltd | Construction | 2020 |
| Sgjw Investments Ltd | Real estate | 2019 |
| SGS Hvac Projects Limited | Manufacturing | 2024 |
| SH Brands Ltd | Manufacturing | 2016 |
| Shaffron Limited | Construction | 2015 |
| Shafiq-Ali R Pradhan Ltd | Health & social care | 2022 |
| Shared Business Services Limited | Professional & scientific | 2012 |
| Sharing Parenting International Ltd | Information & communication | 2021 |
| Sharp Sunshine Tours Limited | Hospitality | 2025 |
| Sharpbridge Properties Limited | Construction | 1987 |
| Sharrons Event Catering Company Limited | Hospitality | 2009 |
| Shaun Valentine Print Limited | Manufacturing | 2012 |
| Shehu Civil Engineering Ltd | Construction | 2022 |
| Sheikh & Co Logistics Ltd | Transport & logistics | 2025 |
| Sherby App Ltd | Information & communication | 2026 |
| Shoreditch Trading Limited | Wholesale & retail | 2019 |
| Showroom Sixty One Limited | Professional & scientific | 2022 |
| Sigma Delta Holdings (ME) Ltd | Financial services | 2025 |
| Silex Consultancy Limited | Other services | 2018 |
| Silver Lady (Brentwood) Ltd | Wholesale & retail | 2011 |
| Silver Project Services Ltd | Professional & scientific | 2019 |
| Silverlanee Ltd | Wholesale & retail | 2026 |
| Simply Audio & Visual Ltd | Wholesale & retail | 2024 |
| Simply Audio Visual Limited | Administrative & support | 2012 |
| Simply Rhino Limited | Wholesale & retail | 2002 |
| SIS Creations Ltd | Arts & recreation | 2019 |
| Sitech Loos London Ltd | Administrative & support | 2012 |
| Sixtyeight Creative Solutions Ltd | Information & communication | 2015 |
| SJ Atkins Ltd | Construction | 2026 |
| Skeewiff Limited | Arts & recreation | 2014 |
| SKO Retail Limited | Wholesale & retail | 2020 |
| Sky Hart Limited | Wholesale & retail | 2024 |
| Skyview Drones Ltd | Professional & scientific | 2026 |
| Small & Cute Nail & Beauty Ltd | Other services | 2019 |
| Small Nail & Beauty Ltd | Other services | 2025 |
| Smiths Holistic Emporium Ltd | Wholesale & retail | 2022 |
| SMK Corp Limited | Wholesale & retail | 2025 |
| Smsolutions-Uk Limited | Information & communication | 2004 |
| Snapdragon Ltd | Information & communication | 2016 |
| Social Flooring Limited | Construction | 2019 |
| Solution Flooring Ltd | Construction | 2019 |
| Solve Property Ltd | Construction | 2024 |
| Solve Sparks Ltd | Administrative & support | 2024 |
| Solvitt Ltd | Water & waste | 2024 |
| Somani Hotels Limited | Hospitality | 2000 |
| Sonrays Investments Ltd | Real estate | 2020 |
| Sopham Partners Ltd | Administrative & support | 2023 |
| Sospecial Occasions Ltd | Administrative & support | 2014 |
| Soundproof Windows Ltd | Construction | 2026 |
| South Coast Concrete Pumping Limited | Administrative & support | 1988 |
| South Country Limited | Information & communication | 2013 |