| Sotto 300 Limited | Professional & scientific | 2009 |
| Soul Sundays CIC | Education | 2024 |
| Soul World Business Ltd | Wholesale & retail | 2019 |
| Soundstem Limited | Construction | 2006 |
| Sourcing Street Ltd | Real estate | 2019 |
| South African Fashion Week Limited | Administrative & support | 2013 |
| South American Agency Limited | Transport & logistics | 1996 |
| South East Elevators Limited | Manufacturing | 2015 |
| South East London Family Mediation Bureau | Health & social care | 1995 |
| South London GAS Limited | Energy | 2007 |
| South London Inspire Futsal Club Limited | Arts & recreation | 2022 |
| South London Kitchen and Bathroom Fitters Ltd | Construction | 2007 |
| South London Self Tapes Limited | Information & communication | 2019 |
| South North Construction & Maintenance Ltd | Construction | 2019 |
| South of the River Records Limited | Information & communication | 2024 |
| South Park Court (Beckenham) RTM Company Limited | Real estate | 2020 |
| South Walk Management Company Limited | Real estate | 1996 |
| Southborough Cafe Ltd | Hospitality | 2018 |
| Southborough Consulting Ltd | Professional & scientific | 2025 |
| Southeast & City Landscapes & Maintenance Limited | Administrative & support | 2005 |
| Southeast GAS Elec Limited | Construction | 2024 |
| Southern Empires Ltd | Construction | 2019 |
| Southern Garden Services Limited | Administrative & support | 2013 |
| Southern Hemisphere Ltd | Administrative & support | 2020 |
| Southern Neuroimaging Ltd | Health & social care | 2018 |
| Southern Scale Models Ltd | Wholesale & retail | 2024 |
| Southern Sun Investments Ltd | Real estate | 2025 |
| Southfleet Window Solutions Ltd | Wholesale & retail | 2023 |
| Southlands Facilities Solutions Ltd | Administrative & support | 2015 |
| Southlands Road Allotments and Gardens Limited | Arts & recreation | 2019 |
| Southlands Tyres Limited | Wholesale & retail | 2013 |
| Southwell Accounting Limited | Professional & scientific | 2016 |
| Southwood Road (Eltham) Management Limited | Households | 1983 |
| Sovereign House Gold Ltd | Wholesale & retail | 2025 |
| Sowgood Limited | Other services | 2021 |
| Spa & Associates Limited | Real estate | 2016 |
| Space 11 Engineer Limited | Information & communication | 2022 |
| Space Property Developments Limited | Construction | 2023 |
| Spark Succeed Coaching and Consulting Ltd | Professional & scientific | 2020 |
| Spark Your Change Ltd | Administrative & support | 2025 |
| Sparkle Care Ltd | Public administration | 2020 |
| Sparklelink Consult Limited | Administrative & support | 2024 |
| Spcomputer Ltd | Information & communication | 2023 |
| Special Needs Design Ltd | Education | 2020 |
| Specialist Heart Clinic UK Limited | Health & social care | 2021 |
| Specialist Property Associates Limited | Real estate | 2019 |
| Specialist Psychology Associates Ltd | Health & social care | 2017 |
| Specialist Psychology Limited | Health & social care | 2019 |
| Spectron Limited | Manufacturing | 1988 |
| Spectrum Broking Services Limited | Administrative & support | 2011 |
| Spectrum Software (UK) Limited | Information & communication | 1994 |
| Spedho Limited | Real estate | 1981 |
| Speed Cosmetics Limited | Wholesale & retail | 2017 |
| Speedy J’S Plates Ltd | Wholesale & retail | 2025 |
| Speedy Visa Limited | Administrative & support | 2025 |
| Speirs Properties Ltd | Real estate | 2025 |
| Spence & Joseph Limited | Professional & scientific | 2021 |
| Spencer Curtis Consulting Ltd | Professional & scientific | 2022 |
| Spencer Lucas Limited | Professional & scientific | 2019 |
| Spenser Mews Owners Limited | Households | 1996 |
| Spice Flavour Bromely Ltd | Hospitality | 2017 |
| Spice Garden of Bromley Ltd | Hospitality | 2011 |
| Spice Kitchen Bromley Ltd | Hospitality | 2022 |
| Spider Ltd | Administrative & support | 1990 |
| Spillways Limited | Construction | 2014 |
| Spiritcraft Ventures Ltd | Wholesale & retail | 2020 |
| Spirited Media Limited | Professional & scientific | 2017 |
| SPJ SET Building Limited | Construction | 2020 |
| Spjl Limited | Administrative & support | 2024 |
| Splash Cleaning Services Ltd | Other services | 2014 |
| Splash Damage Group Limited | Information & communication | 2015 |
| Splash Damage Limited | Information & communication | 2001 |
| Splendent Care Limited | Health & social care | 2006 |
| Splix TRD Limited | Wholesale & retail | 2025 |
| Spms Cleaning Ltd | Administrative & support | 2026 |
| Spomb Consultancy Limited | Professional & scientific | 2018 |
| Sprayviation Ltd | Construction | 2025 |
| Spread Eagle Developments Limited | Construction | 2026 |
| Spright Capital Ltd | Professional & scientific | 2023 |
| Spring Croft Enterprises Limited | Health & social care | 2016 |
| Springbourne Management Company Limited | Households | 1982 |
| Springfield Gardens (West Wickham) Management Limited | Households | 2007 |
| Springhaven Limited | Health & social care | 2025 |
| Springstock Housing Ltd | Real estate | 2026 |
| Sprint Partners Consultancy Ltd | Professional & scientific | 2024 |
| Spruce Park Management Company Limited | Households | 1984 |
| SPS IT Ltd | Information & communication | 2019 |
| SPS Property Investment Ltd | Real estate | 2021 |
| SPS Style Ltd | Other services | 2016 |
| Spudbae Ltd | Hospitality | 2024 |
| Spydr Ltd | Manufacturing | 2026 |
| SQ Jobs Ltd | Construction | 2019 |
| Sqaurecut Solutions 59 4 Ltd | Real estate | 2025 |
| Squally Ltd. | Professional & scientific | 2022 |
| Square Eyes Post Production Limited | Information & communication | 2019 |
| Square One Lodging Ltd | Financial services | 2019 |
| Square One London & Kent Ltd | Construction | 2023 |
| Squarecut Solution Properties Limited | Real estate | 2025 |
| Squarecut Solutions 2 1 Ltd | Real estate | 2025 |
| Squarecut Solutions 37 Crown Ltd | Real estate | 2026 |