| Semmizuk Limited | Transport & logistics | 2025 |
| Sempervirens Aroma Ltd | Health & social care | 2021 |
| Senleo Services Ltd | Transport & logistics | 2026 |
| Sensations for Generations CIC | Education | 2025 |
| Sergiu Obada Ltd | Construction | 2019 |
| Serif Onur Ltd | Hospitality | 2019 |
| Serifoglu Property Partnership Limited | Real estate | 2023 |
| Service Point 17 Limited | Wholesale & retail | 2024 |
| Servicepoint Bobbing Ltd | Wholesale & retail | 2026 |
| SES Electrical (Kent) Ltd | Construction | 2023 |
| SET in Stone ( Kent ) Limited | Other services | 2012 |
| Setteundici Ltd | Wholesale & retail | 2024 |
| Seven Property Group Ltd | Real estate | 2025 |
| Sevenoaks & District Motor Club Limited | Arts & recreation | 1967 |
| Seventy Homes Limited | Real estate | 2022 |
| Seventyseven Medical Services Limited | Health & social care | 2023 |
| Sevi Construction Logistics Ltd | Construction | 2021 |
| Sexplay Theatre Play Limited | Arts & recreation | 2025 |
| Seyrely Care Services Limited | Health & social care | 2022 |
| Sg.Accounts Ltd | Professional & scientific | 2023 |
| Sgklifting Ltd | Professional & scientific | 2026 |
| SGN Electrical Limited | Manufacturing | 2003 |
| Shabskitchen Limited | Hospitality | 2019 |
| Shadeb Ltd | Other services | 2022 |
| Shakespeare Design Solutions Ltd | Professional & scientific | 2014 |
| Shalu Properties Ltd | Real estate | 2020 |
| Shan Food Palace Ltd | Hospitality | 2024 |
| Shan Services Ltd | Wholesale & retail | 2015 |
| Shanlec Services Limited | Construction | 2018 |
| Shanti Real Estate Ltd | Real estate | 2019 |
| Share the Care Ltd | Health & social care | 2015 |
| Sharp Accountancy Services (UK) Ltd | Professional & scientific | 2012 |
| Sharp Products Ltd | Wholesale & retail | 2023 |
| Sharp Styles Barbers Limited | Other services | 2018 |
| Sharp TAN Ltd | Other services | 2022 |
| Sharsted Motors LP | | 2016 |
| Shaunproperty Ltd | Real estate | 2025 |
| Shaw Property Maintenance Limited | Construction | 2026 |
| Shawafco Limited | Real estate | 2020 |
| Sheehan Carpentry and Construction Limited | Construction | 2022 |
| Sheppey Gateway Ltd | Other services | 2022 |
| Shirley's Bakes Ltd | Manufacturing | 2019 |
| Shomay UK Ltd | Real estate | 2025 |
| Shortlands Gardens Ltd | Administrative & support | 2024 |
| Shumi (Ashford) Limited | Hospitality | 2007 |
| Shumi Estates Limited | Real estate | 2007 |
| Shurland Meadow Sports Club Ltd | Hospitality | 2021 |
| Shutterworks Imaging Limited | Professional & scientific | 2025 |
| Si-Drama Limited | Arts & recreation | 1989 |
| SIA Retail Limited | Wholesale & retail | 2016 |
| SIA90 Limited | Transport & logistics | 2018 |
| Sianti Management Systems Limited | Information & communication | 1995 |
| Sickeeze Ltd | Manufacturing | 2006 |
| Sidekick (Kent) Ltd | Administrative & support | 2020 |
| Sieago Ltd | Real estate | 2023 |
| Sigma Enterprises Limited | Wholesale & retail | 1984 |
| Sigma UK Distribution Limited | Wholesale & retail | 2014 |
| Sign Trade Supplies Limited | Wholesale & retail | 2000 |
| Signs and Wraps Ltd | Manufacturing | 2014 |
| Signwriters International Ltd | Professional & scientific | 2023 |
| Sihoni Limited | Information & communication | 2023 |
| SIJ Ravne Systems (UK) Limited | Administrative & support | 2010 |
| Silverstones Properties Limited | Real estate | 2025 |
| Silvervane Ltd | Professional & scientific | 2025 |
| Silverwood Computer Services Limited | Information & communication | 1995 |
| Silviu Services Ltd | Transport & logistics | 2022 |
| Simmonds Engineering Limited | Manufacturing | 2017 |
| Simone Marie Ltd | Arts & recreation | 2025 |
| Simplex Healthcare Limited | Health & social care | 2020 |
| Simply Cars Ltd | Wholesale & retail | 2022 |
| Simply IT Solutions Limited | Information & communication | 2012 |
| Simply Property Acquisitions Limited | Real estate | 2025 |
| Singh Ltd | Agriculture & fishing | 2015 |
| Single & Married With a Life Limited | Education | 2026 |
| Sinnat Holding Ltd | Financial services | 2024 |
| SIS Trans UK Ltd | Transport & logistics | 2016 |
| Site Hotels Ltd | Hospitality | 2014 |
| Sitti Salon Escape Limited | Other services | 2023 |
| Sittilogs Limited | Agriculture & fishing | 2024 |
| Sittingbourne Community Radio Limited | Information & communication | 2008 |
| Sittingbourne Food Investments Ltd | Hospitality | 2025 |
| Sittingbourne Football Club Limited | Arts & recreation | 2018 |
| Sittingbourne Golf Centre Limited | Arts & recreation | 2012 |
| Sittingbourne Nails Limited | Other services | 2019 |
| Sittingbourne Osteopathy Ltd | Health & social care | 2014 |
| Sittingbourne Retail Park Limited | Real estate | 1991 |
| Sittingbourne Self Storage Limited | Administrative & support | 2023 |
| Sittingbourne Services Limited | Wholesale & retail | 2019 |
| Sittivapes Limited | Wholesale & retail | 2022 |
| SJB Roofing Services Limited | Construction | 2010 |
| SJL Aviation Ltd | Manufacturing | 2014 |
| SK Landscape Gardening Ltd | Administrative & support | 2023 |
| Skan Trade Ltd | Wholesale & retail | 2025 |
| SKC Engineering Limited | Manufacturing | 2010 |
| Skeye ASI Ltd | Professional & scientific | 2012 |
| Skiin LAB Ltd | Other services | 2022 |
| Skilled Brickwork Ltd | Construction | 2024 |
| Skingredients Group Limited | Wholesale & retail | 2021 |
| Skyknit Consults Ltd | Health & social care | 2024 |
| Skyline Taxi Sittingbourne Ltd | Wholesale & retail | 2025 |