| Sage Promotions Limited | Arts & recreation | 2017 |
| Sailing Chandlery Ltd | Wholesale & retail | 2017 |
| Sales Geek Waltham Abbey Ltd | Professional & scientific | 2023 |
| Salon Hygiene Solutions (Worldwide) Ltd | Wholesale & retail | 2025 |
| Samak Properties Limited | Real estate | 2023 |
| Same Day Loans Ltd | Professional & scientific | 2024 |
| Samuel Hanes Limited | Professional & scientific | 2023 |
| Sanconsultanci Limited | Professional & scientific | 2021 |
| Sanctum Events Ltd | Administrative & support | 2023 |
| Sandon Leigh Limited | Professional & scientific | 2016 |
| Sanway Limited | Hospitality | 2024 |
| Sapphire Essence Care Ltd | Health & social care | 2020 |
| Sapphire Medical Staffing Ltd | Administrative & support | 2024 |
| Sapphire Security Systems (Essex) Limited | Administrative & support | 2015 |
| Sarah Simmonds Interiors Ltd | Professional & scientific | 2013 |
| Saucy Sisters Limited | Manufacturing | 2017 |
| Saunders Roofing Limited | Construction | 2020 |
| Savs Ltd | Transport & logistics | 2002 |
| Saxon Property Ltd | Real estate | 2020 |
| SAY NO to the TOE Ltd | Manufacturing | 2024 |
| SB Education Consultancy & Training Limited | Education | 2022 |
| SC31 Limited | Real estate | 2011 |
| Scoble Hart Ltd | Professional & scientific | 2020 |
| Scope Construction and Development Limited | Construction | 2022 |
| Scott Davis & Sons Ltd | Construction | 2025 |
| Scott Piling Limited | Construction | 1997 |
| Screen VR Studios Ltd | Information & communication | 2024 |
| Scribemat Limited | Information & communication | 2024 |
| SCS Private Limited | Information & communication | 2018 |
| SDC Fabrications Ltd | Manufacturing | 2014 |
| SDS Services (Essex) Limited | Construction | 2001 |
| Sealandair Transport Company Limited | Transport & logistics | 1993 |
| Sealant Doctor Ltd | Construction | 2025 |
| Sean Leverett Fishing Tackle Ltd | Wholesale & retail | 2023 |
| Seaside Flooring Ltd | Construction | 2025 |
| Seasons Coco Limited | Administrative & support | 2017 |
| Seastar Limited | Construction | 1972 |
| Seaview Heights Ltd | Construction | 2024 |
| Sebastian & Jacob Property Developers Ltd | Real estate | 2021 |
| Secrets Hairdressing Ltd | Other services | 2008 |
| Sectorbridge Recruitment Ltd | Administrative & support | 2026 |
| Secure Your Build Limited | Extraterritorial | 2023 |
| Securitall Ltd | Administrative & support | 2014 |
| Security Training Authority Limited | Administrative & support | 2023 |
| Seddon Flooring Limited | Construction | 1999 |
| Sefil Haydo Limited | Hospitality | 2018 |
| Selection Box Limited | Wholesale & retail | 2025 |
| Selman Builders Limited | Construction | 2025 |
| Sentinel Training UK Ltd | Education | 2021 |
| Sentral Studios Ltd | Information & communication | 2023 |
| Serendipity Imports Ltd | Wholesale & retail | 2019 |
| Serene Fitness Ltd | Arts & recreation | 2018 |
| Service Certainty Imageproof Ltd | Administrative & support | 2010 |
| Service Certainty Ltd | Professional & scientific | 2009 |
| Service Level Management Limited | Information & communication | 1994 |
| Sethu Investment Advisors Limited | Professional & scientific | 2013 |
| Sfkw Limited | Real estate | 2020 |
| Sgkr Investments Ltd | Real estate | 2021 |
| SH Contemporary Ltd | Professional & scientific | 2020 |
| Shades of SHO Limited | Real estate | 2021 |
| Shalommotorbikesalesandparts Limited | Wholesale & retail | 2025 |
| Shalu Ltd | Wholesale & retail | 2026 |
| Shan Payne Mortgages Limited | Financial services | 2021 |
| Sharn Properties Ltd | Real estate | 2024 |
| Sharp Property Management Ltd | Real estate | 2019 |
| Shaun Francis Properties Limited | Real estate | 2024 |
| Shavik Enterprises Ltd | Wholesale & retail | 2022 |
| Shaw Inspire Ltd | Real estate | 2024 |
| Shazam Automotive Ltd | Extraterritorial | 2024 |
| Shazam Composites Ltd | Extraterritorial | 2024 |
| Shazam Repairs Ltd | Construction | 2024 |
| Shelama Care Ltd | Health & social care | 2026 |
| Sheldrake Brickwork Limited | Construction | 1997 |
| Shfd Limited | Wholesale & retail | 2019 |
| Shirley Anthony Ltd | Financial services | 2003 |
| Shoebury Carriage Company Ltd | Wholesale & retail | 2003 |
| Shoebury Tyre & Auto Ltd | Extraterritorial | 2006 |
| Shoestring Films Limited | Information & communication | 2010 |
| Shornj Management Ltd | Professional & scientific | 2021 |
| Shout Social Media Limited | Information & communication | 2026 |
| Show UP Productions Ltd | Administrative & support | 2016 |
| SI & DL Ltd | Administrative & support | 2014 |
| Siah Lifestyle Ltd | Other services | 2025 |
| Sickly Sisters Limited | Manufacturing | 2022 |
| Signature Bathrooms Essex Ltd | Construction | 2026 |
| Sillett Solutions Limited | Information & communication | 2011 |
| Silver Church Limited | Professional & scientific | 2021 |
| Silver Cloud Data Solutions Limited | Information & communication | 2013 |
| Silver Key Homes Ltd | Construction | 2013 |
| Silverback Professional Services Ltd | Water & waste | 2024 |
| Simfin Mortgages Ltd | Financial services | 2012 |
| Simon Assets Ltd | Real estate | 2024 |
| Simple Service Automotive Ltd | Wholesale & retail | 2013 |
| Simply Just Entertainment Ltd | Arts & recreation | 2025 |
| Simply the Pest LDN Ltd | Other services | 2023 |
| Simply the Pest Maintenance Limited | Administrative & support | 2019 |
| Simply Walls Ltd | Real estate | 2019 |
| Simree IT Limited | Information & communication | 2019 |
| Simtonic Financial Solutions Limited | Financial services | 2015 |
| Singleton Property Management Ltd | Real estate | 2024 |