| Sarah Wenman Limited | Administrative & support | 2006 |
| Sarana Ltd | Health & social care | 2015 |
| Sarbar Limited | Real estate | 1988 |
| Sarena Water Tanks Ltd | Water & waste | 2023 |
| Sark Consulting Ltd | Professional & scientific | 2023 |
| Sarnitha Properties Limited | Real estate | 2024 |
| Saroja Software Solutions Ltd | Information & communication | 2011 |
| Sart Consultancy Ltd | Construction | 2017 |
| SAS Accounting Services Limited | Professional & scientific | 2013 |
| SAS Accounting Services SBS Limited | Professional & scientific | 2019 |
| SAS Education Consultancy Ltd | Education | 2025 |
| SAS FEE Protection Limited | Professional & scientific | 2017 |
| SAS Tax and Accountancy Ltd | Professional & scientific | 2025 |
| Sasi Supermarket Limited | Wholesale & retail | 2024 |
| Sass Research & Information Systems Ltd | Information & communication | 2025 |
| Saturday Garage Ltd | Wholesale & retail | 2024 |
| Saude Care Ltd | Health & social care | 2018 |
| Sauer Compressors UK Limited | Wholesale & retail | 2013 |
| Saumil Patel Ltd | Information & communication | 2015 |
| Saunders Electrical Services Ltd | Construction | 2021 |
| Savachi Services Limited | Health & social care | 2013 |
| Savannah Cars & Commercial Ltd | Extraterritorial | 2024 |
| Savannah Cars Ltd | Wholesale & retail | 2013 |
| Savannah Land Ltd | Construction | 2025 |
| Savannah Meat's Ltd | Wholesale & retail | 2007 |
| Savannah Property Investments Ltd | Construction | 2021 |
| Savmont Developments Ltd | Real estate | 2021 |
| Savocardio Limited | Health & social care | 2019 |
| Savoir Socials Ltd | Professional & scientific | 2024 |
| Savvy Business Communications Limited | Administrative & support | 2010 |
| Savvy Homes Ltd | Real estate | 2024 |
| Saxon Court (Bull Lane) Management Limited | Households | 1988 |
| Saxon Green Residents Management Company Limited | Households | 2016 |
| Saxon Square Management Company Limited | Households | 2003 |
| Saxons Badminton CIC | Arts & recreation | 2025 |
| Saxons Lettings & Management Limited | Real estate | 2003 |
| Saxons Property Services (Colchester) Limited | Professional & scientific | 2002 |
| Saya Vairav Ltd | Wholesale & retail | 2022 |
| SB Corporations International Limited | Professional & scientific | 2016 |
| SB Land Holdings Ltd | Real estate | 2016 |
| SB Lounge Ltd | Hospitality | 2024 |
| SBF Consultants Limited | Professional & scientific | 2008 |
| Sbhardwaj Ltd | Health & social care | 2021 |
| Sbjr Holdings Ltd | Professional & scientific | 2019 |
| SBL Holdings Limited | Administrative & support | 2022 |
| SC & AA Ltd | Hospitality | 2023 |
| SC Adivisory Limited | Construction | 2022 |
| SC Recovery Services Ltd | Wholesale & retail | 2021 |
| SC Solutions Limited | Professional & scientific | 2025 |
| Scaf Plumbing & Heating Limited | Construction | 2022 |
| Scale I/O Ltd | Administrative & support | 2021 |
| Scale Models International Ltd | Professional & scientific | 2003 |
| Scale Models Weston Ltd | Administrative & support | 2003 |
| Scale Rulers Limited | Professional & scientific | 2006 |
| Scale UP Coaching Limited | Professional & scientific | 2017 |
| Scallywags Day Nursery (Essex) Limited | Education | 1996 |
| Scandi Home Limited | Wholesale & retail | 2024 |
| Scandi Imports Ltd | Wholesale & retail | 2024 |
| Scanlift Limited | Manufacturing | 1991 |
| Scarfe Holdings Limited | Financial services | 2019 |
| Scariam Limited | Real estate | 2016 |
| Scarred NOT Broken Ltd | Wholesale & retail | 2025 |
| SCB Essex Limited | Construction | 2026 |
| SCB IT Limited | Information & communication | 2019 |
| Sccs Global Limited | Wholesale & retail | 2025 |
| Scent Away Limited | Manufacturing | 2021 |
| Scent Heaven Ltd | Wholesale & retail | 2019 |
| Scents Asian Limited | Manufacturing | 2021 |
| Schofield Physiotherapy Limited | Health & social care | 2026 |
| Schofield Roofing Ltd | Construction | 2019 |
| Scholarbridge Academic Services Ltd | Education | 2026 |
| Schomberg Festival Catering Ltd | Hospitality | 2022 |
| School Tech Support Ltd | Information & communication | 2018 |
| Schroder Nominees Limited | Financial services | 1927 |
| SCJ Cleaning Ltd | Administrative & support | 2025 |
| SCK Projects Limited | Construction | 2025 |
| Scomad Ltd | Transport & logistics | 2025 |
| Sconch Ltd | Wholesale & retail | 2024 |
| Scope 360 Ltd | Education | 2009 |
| Scope in Colchester and Tendring | Health & social care | 1995 |
| Scope Joinery Limited | Manufacturing | 2000 |
| Scopmac Ltd | Wholesale & retail | 2025 |
| Scorpius Books Limited | Information & communication | 2025 |
| Scott BB Limited | Manufacturing | 1973 |
| Scott BH Limited | Hospitality | 2012 |
| Scott Bird Engineering Ltd | Construction | 2024 |
| Scott BMG Limited | Administrative & support | 2010 |
| Scott Brundall BS Limited | Other services | 2012 |
| Scott James Hair Studio Ltd | Other services | 2025 |
| Scott Residential Ltd | Construction | 2009 |
| Scott, George & Gilchrist Management Ltd | Real estate | 2021 |
| Scotties Farm Group Ltd | Hospitality | 2024 |
| Scotties Farm Ltd | Agriculture & fishing | 2022 |
| Scotts Plumbing & Heating Services Limited | Construction | 2024 |
| Scoutmind Limited | Information & communication | 2026 |
| Scr-Consulting (UK) Ltd | Professional & scientific | 2013 |
| SCREEN19 Ltd | Wholesale & retail | 2020 |
| Scrutton Bland Financial Services Limited | Financial services | 1976 |
| Scrutton Bland Insurance Brokers Limited | Financial services | 2018 |
| SCS Plumbing and Heating Ltd | Construction | 2025 |