| Sea Salt PUB Co Limited | Hospitality | 2019 |
| Sea Shanty (Kent) Ltd | Manufacturing | 2024 |
| Sea Wing Freight Ltd | Transport & logistics | 2021 |
| Seadotdev Limited | Information & communication | 2023 |
| Sealladh Meicli Blueberry Farm Limited | Agriculture & fishing | 2026 |
| Seamail Ltd | Extraterritorial | 2011 |
| Seamless Systems Limited | Manufacturing | 2024 |
| Sean Davey Electrical Limited | Construction | 2012 |
| Sean Pembroke Associates Ltd | Professional & scientific | 2020 |
| Seapoint Canoe Centre | Arts & recreation | 2007 |
| Seapost Ltd | Extraterritorial | 2011 |
| Secret Garden Enterprises Ltd | Hospitality | 2006 |
| Secret Motion Ltd | Information & communication | 2025 |
| Secure Access Protection Limited | Administrative & support | 2013 |
| Secure Storage Solutions (Birchwood) Limited | Agriculture & fishing | 2020 |
| Secure Storage Solutions (Kent) Limited | Other services | 2018 |
| Secure Swimwear Ltd | Wholesale & retail | 2024 |
| Secure Working Ltd | Information & communication | 2023 |
| Securebrix Limited | Information & communication | 2022 |
| Security & Tech Solutions Ltd | Information & communication | 2019 |
| Security Drone Surveillance and Recruitment Ltd | Administrative & support | 2025 |
| Sedgemead House Aesthetic Services Limited | Health & social care | 2012 |
| Seekwise Limited | Real estate | 2015 |
| Seges & D Ltd | Wholesale & retail | 2018 |
| Segue Accountants Ltd | Professional & scientific | 2026 |
| Segura Capital Limited | Administrative & support | 2021 |
| Sehmangli Ltd | Wholesale & retail | 2025 |
| SEI Tech International Ltd | Professional & scientific | 2025 |
| Seika Media Limited | Professional & scientific | 2020 |
| Seki Limited | Construction | 2019 |
| Seku Properties Ltd | Real estate | 2021 |
| Select Property Maintenance Kent Limited | Construction | 2004 |
| SELECTED2 Limited | Extraterritorial | 2016 |
| Selene KIM Ltd | Information & communication | 2026 |
| Sellective Ltd | Professional & scientific | 2019 |
| Selling B2L Limited | Real estate | 2020 |
| Selling Developments (Group) Limited | Financial services | 2018 |
| Selling Developments (Holdings) Limited | Financial services | 2022 |
| Selling Developments (Kent) Limited | Construction | 2015 |
| Selling Developments Limited | Construction | 2009 |
| Selling Group (Kent) Limited | Financial services | 2020 |
| Selling Group Limited | Financial services | 2020 |
| Selling Homes (Kent) Limited | Real estate | 2020 |
| Selling Property (21) Limited | Construction | 2026 |
| Selling Property Limited | Construction | 2020 |
| Selsey Spice Ltd | Hospitality | 2014 |
| SEM Accounts Limited | Professional & scientific | 2019 |
| Seniors Helping Seniors (UK) Limited | Health & social care | 2013 |
| Senseless Nutrition Ltd | Manufacturing | 2025 |
| Sensorii Limited | Professional & scientific | 2013 |
| Senstation Ltd | Wholesale & retail | 2022 |
| Senta Imaging Private Limited | Health & social care | 2024 |
| Sentinal Services PM Ltd | Construction | 2025 |
| Sentinel Financial Services Limited | Financial services | 2012 |
| Seonat Ltd | Professional & scientific | 2026 |
| SER PIL Ltd | Real estate | 2025 |
| Serendib Legal Solutions Ltd | Professional & scientific | 2012 |
| Serene Suffolk Retreats Ltd | Real estate | 2025 |
| Sereneskinclinic Limited | Other services | 2025 |
| Serious About Parts Limited | Wholesale & retail | 2022 |
| Serious Graphics Limited | Manufacturing | 2014 |
| Serious Waste Holdings Limited | Professional & scientific | 2020 |
| Serranova Limited | Administrative & support | 2013 |
| Seru Investments Limited | Real estate | 2024 |
| Servan 49 Limited | Hospitality | 2025 |
| Servers and Networking UK Ltd | Construction | 2025 |
| Serviced Apartment Extras Ltd | Real estate | 2019 |
| Services for Landlord Ltd | Real estate | 2018 |
| SES Electrical (Southern) Limited | Construction | 2014 |
| Sessami Ltd | Information & communication | 2022 |
| Setapp Limited | Information & communication | 2024 |
| Sethi Telecom Limited | Manufacturing | 2017 |
| SEUNNIS1 Ltd | Health & social care | 2025 |
| Seva Estates Limited | Construction | 2020 |
| Seva Holding Limited | Real estate | 2019 |
| Seva Rail Services Ltd | Construction | 2015 |
| Seven Seas Worldwide Group Limited | Financial services | 2011 |
| Seven Seas Worldwide Ltd | Transport & logistics | 1996 |
| Seven Seas Worldwide Services Limited | Extraterritorial | 1991 |
| Sevenoaks Swimming Pools Ltd | Construction | 2021 |
| Severn Stone Ornaments Limited | Manufacturing | 2024 |
| Sewa Heating Services Ltd | Construction | 2019 |
| Sewaro Property Holdings Limited | Real estate | 2026 |
| Sexton's Ltd | Construction | 2025 |
| SF 3PL Ltd | Wholesale & retail | 2018 |
| SF Elite Ltd | Other services | 2010 |
| SF Ingredients Ltd | Wholesale & retail | 2024 |
| SF Media & PR Ltd | Professional & scientific | 2019 |
| SF Pet Nutrition Ltd | Wholesale & retail | 2018 |
| SF Trading Limited | Wholesale & retail | 2007 |
| SFC Ashford Limited | Hospitality | 2025 |
| Sfdc Data Services Ltd | Information & communication | 2026 |
| Sfge (Tower) Limited | Real estate | 2019 |
| Sfge Properties Limited | Real estate | 2015 |
| SG Bell Consulting Ltd | Professional & scientific | 2025 |
| SG Utilities Ltd | Construction | 2018 |
| SG Web Limited | Information & communication | 2023 |
| SGF Ventures Ltd | Professional & scientific | 2024 |
| SGM Venture Holdings LLP | | 2023 |
| Sgpt Ltd | Health & social care | 2020 |