| Shkar Convenience Stores Ltd | Wholesale & retail | 2026 |
| Shore Construction Services Ltd | Construction | 2021 |
| Shore Media Limited | Professional & scientific | 2022 |
| Shreeve Commercial Limited | Real estate | 2018 |
| Shreeve Commercial Properties Limited | Real estate | 2024 |
| Shtk Limited | Energy | 2019 |
| Sibylla (EA) Limited | Other services | 2016 |
| Side Wick Ltd | Manufacturing | 2025 |
| Sigma East Anglia Ltd | Construction | 2022 |
| Simple’S Spraypainting Services Ltd | Extraterritorial | 2025 |
| Simply Diaries Limited | Manufacturing | 2000 |
| Simply Maintenance Limited | Extraterritorial | 1998 |
| Simply Webs Online Limited | Information & communication | 2016 |
| Sizzlers Cafe Ltd | Hospitality | 2025 |
| SJD Engineering Limited | Construction | 2017 |
| SJK Communications Limited | Information & communication | 1997 |
| SJL Hydraulic Services Ltd | Real estate | 2022 |
| Skin Graphics Limited | Other services | 2001 |
| Skyline Food Experts Ltd | Hospitality | 2025 |
| Skyward Fire Ltd | Wholesale & retail | 2017 |
| SLB Cars Limited | Transport & logistics | 2014 |
| SLC Structural & Piping Services Ltd | Mining & quarrying | 2024 |
| Slimdril Limited | Administrative & support | 1998 |
| Sljd Limited | Real estate | 2014 |
| SLM Energy Services Limited | Professional & scientific | 2026 |
| SLR Piping Services Limited | Construction | 2015 |
| SM Marine Geophysical Services Ltd | Professional & scientific | 2015 |
| Smart MOT Garage Limited | Wholesale & retail | 2022 |
| Smart Properties (Lowestoft) Limited | Households | 2013 |
| Smart Refinish Limited | Wholesale & retail | 2007 |
| Smarter Blanks Limited | Wholesale & retail | 2023 |
| Smith Bros Timber (East Anglia) Limited | Wholesale & retail | 1992 |
| SMP Consultancy Ltd | Professional & scientific | 2021 |
| SMS Auto Holdings Limited | Financial services | 2025 |
| Snetterton Auto Services Limited | Wholesale & retail | 2023 |
| Social Impact Xchange Ltd | Professional & scientific | 2025 |
| Sojoe Ltd | Real estate | 2022 |
| SOLAR33 Tanning Limited | Other services | 2025 |
| Solarwise Care Ltd | Professional & scientific | 2022 |
| Sole Bay Diving & Marine Ltd | Other services | 2023 |
| Solers Palaestra Ltd | Administrative & support | 2007 |
| Solo Oilfield Services Limited | Mining & quarrying | 1998 |
| Solvency II Consulting Ltd | Information & communication | 2015 |
| Somerleyton Marina Limited | Administrative & support | 2012 |
| Sonmead Builders Limited | Construction | 1972 |
| South Pier Lowestoft Limited | Other services | 2015 |
| Southby Holdings Limited | Manufacturing | 2001 |
| Southern Commissioning Limited | Construction | 2002 |
| Southern Crewing Services Limited | Administrative & support | 1993 |
| Southern HUT Ltd | Hospitality | 2023 |
| Southern Merchants Limited | Administrative & support | 2010 |
| Southwold Bodywork Repairs Ltd | Wholesale & retail | 2019 |
| Southwold Florists Limited | Wholesale & retail | 2026 |
| Southwold Retreats Limited | Real estate | 2006 |
| Southwold Treatment Rooms Limited | Health & social care | 2021 |
| Sovereign Asset Developments Limited | Real estate | 2025 |
| Sovereign Groundworks & Construction Limited | Construction | 2023 |
| Sovereign Plumbing Limited | Construction | 1995 |
| Sovereign Plumbing Partners Limited | Financial services | 2024 |
| Sovereign Vehicle Logistics Limited | Transport & logistics | 2026 |
| Spacex Cleaning Ltd | Administrative & support | 2021 |
| Spanner Made IT Ltd | Information & communication | 2024 |
| Sparklez Ltd | Administrative & support | 2022 |
| Sparrowhawk Training Services Ltd | Education | 2015 |
| Specialist Access Onshore/Offshore Ltd | Mining & quarrying | 2024 |
| Spectre Property Limited | Real estate | 2020 |
| Spectrum on Air Ltd | Information & communication | 2015 |
| Speke 247 Ltd | Arts & recreation | 2021 |
| Speke 247 Trading Ltd | Arts & recreation | 2022 |
| Spire Accounting Ltd | Professional & scientific | 2023 |
| Spot on Window Cleaning Services Ltd | Administrative & support | 2023 |
| Spraytherm Ltd | Construction | 2023 |
| Spring Lodge (Care Home) Limited | Health & social care | 1997 |
| Springford S P Limited | Wholesale & retail | 2005 |
| Spry Management Transport Ltd | Transport & logistics | 2026 |
| Sputnik Control Loop Solutions Ltd | Manufacturing | 2014 |
| ST Agnes Biltong Limited | Manufacturing | 2025 |
| ST. Nicholas Court (Lowestoft) Limited | Households | 1990 |
| Stables Restaurant (Corton) Ltd | Hospitality | 2019 |
| Stag Building Company Limited | Construction | 2016 |
| Stagesets Limited | Manufacturing | 2011 |
| Stammers Engineering Limited | Professional & scientific | 2018 |
| Standard Furniture Limited | Wholesale & retail | 2018 |
| Stanley Street Vehicles Ltd | Wholesale & retail | 2025 |
| Starfrost (UK) Limited | Manufacturing | 1995 |
| Starkemp Limited | Real estate | 1995 |
| Stars of the Stage Performing Arts School Ltd | Arts & recreation | 2022 |
| Stateside Traders Limited | Hospitality | 2023 |
| Station Regeneration East Community Interest Company | Other services | 2018 |
| Steel & Co (East Anglia) Accommodation Services Ltd | Households | 2020 |
| Steel & Co (East Anglia) Financial Services Limited | Financial services | 2016 |
| Steel & Co (East Anglia) Limited | Real estate | 2016 |
| Steel Masters (Norwich) Ltd | Manufacturing | 2003 |
| Steep Tea Ltd | Wholesale & retail | 2024 |
| Stemma Limited | Construction | 2019 |
| Steria Consulting Ltd | Professional & scientific | 2021 |
| Sterling Brundall Holdings Ltd | Administrative & support | 2026 |
| Sterling E a Limited | Manufacturing | 2019 |
| Sterling Properties and Lettings Limited | Real estate | 2024 |
| Steve Bailey Groundworks Limited | Construction | 2008 |