| Suffolk Sound Limited | Information & communication | 2024 |
| Suffolk Sound Radio CIC | Information & communication | 2024 |
| Suffolk Sound Radio Group Ltd | Information & communication | 2023 |
| Suffolk Sports Equipment & Clothing Ltd | Wholesale & retail | 2024 |
| Suffolk Steam Ltd | Professional & scientific | 2018 |
| Suffolk Strength Academy Ltd | Health & social care | 2014 |
| Suffolk Support Ltd | Health & social care | 2025 |
| Suffolk Sushi Limited | Hospitality | 2023 |
| Suffolk Teaching Solutions Limited | Administrative & support | 2026 |
| Suffolk Tennis Courts Limited | Construction | 2012 |
| Suffolk Tennis Funding Limited | Arts & recreation | 1993 |
| Suffolk Trade Limited | Wholesale & retail | 2013 |
| Suffolk Trade Supplies Ltd | Wholesale & retail | 2025 |
| Suffolk Travel Ltd | Transport & logistics | 2020 |
| Suffolk Trees & Hedges Limited | Extraterritorial | 2010 |
| Suffolk Union Services Limited | Wholesale & retail | 2010 |
| Suffolk User Forum | Health & social care | 2009 |
| Suffolk Vehicle Repairs Ltd | Wholesale & retail | 2025 |
| Suffolk Wealth Management Limited | Financial services | 2014 |
| Suffolk Welding & Fabrication Ltd | Manufacturing | 2020 |
| Suffolk Wildlife Trust | Arts & recreation | 1961 |
| Suffolk Will Services Limited | Professional & scientific | 2019 |
| Suffolk Wills and Estate Planning Ltd | Professional & scientific | 2021 |
| Suffolk Woman's Wellness Centre Limited | Other services | 2018 |
| Suffolk Yacht Harbour Limited | Arts & recreation | 1967 |
| Sugar N Spice Cosmetics Ltd | Other services | 2023 |
| Sugarcraft World Limited | Wholesale & retail | 2008 |
| Suite Generation Limited | Information & communication | 2025 |
| Suite Holding Limited | Information & communication | 2025 |
| Suite Investments Limited | Financial services | 2025 |
| Suitewise Limited | Information & communication | 2024 |
| Sulavi Ltd | Information & communication | 2026 |
| Suli Barber Ipswich Ltd | Other services | 2026 |
| Suli Property Ltd | Real estate | 2025 |
| Sullys Day Care Ltd | Other services | 2024 |
| Sultan Food Store Ltd | Wholesale & retail | 2025 |
| Summiqen Formats Ltd | Information & communication | 2026 |
| Summit Advisory Group Ltd | Wholesale & retail | 2025 |
| Summit Civil Engineering Ltd | Construction | 2025 |
| Summit Construction Suffolk Limited | Construction | 2024 |
| Summit Lifestyle Ltd | Administrative & support | 2025 |
| Summit Security Limited | Administrative & support | 2025 |
| Sun Kebab Ipswich Ltd | Hospitality | 2025 |
| Sun Society Tanning Ltd | Other services | 2026 |
| Sun Speedy Ltd | Wholesale & retail | 2023 |
| Sunfatt Chinese Ltd | Hospitality | 2025 |
| Sunflower Escapes Ltd | Administrative & support | 2020 |
| Sunrise Technologists Limited | Professional & scientific | 2006 |
| Sunshine Guides Limited | Information & communication | 2016 |
| Sunshine Security Investment Ltd | Financial services | 2023 |
| Sunsprite Homes Ltd | Real estate | 2020 |
| Suntasticuk Ltd | Hospitality | 2023 |
| Sup'R'Setgym Ltd | Wholesale & retail | 2023 |
| Supercellsro Ltd | Wholesale & retail | 2025 |
| Superfood Shop Ltd | Wholesale & retail | 2024 |
| Superhero Brands Ltd | Administrative & support | 2025 |
| Superiorstirling Limited | Manufacturing | 2023 |
| Supernova Software Consultancy Ltd | Information & communication | 2019 |
| Superstart AGY Limited | Administrative & support | 2025 |
| Superstructures (East Anglia) Limited | Professional & scientific | 2011 |
| Superyacht Composites Limited | Manufacturing | 2022 |
| Superyacht Holdings Limited | Financial services | 2022 |
| Superyacht Tenders and Toys Limited | Wholesale & retail | 2011 |
| Support Care of Older People Limited | Health & social care | 2004 |
| Support Haven Ltd | Administrative & support | 2017 |
| Support Skills Training Ltd | Education | 2024 |
| Support Unlimited UK Ltd | Health & social care | 2015 |
| Supportscope Limited | Health & social care | 2023 |
| Supralimina Limited | Professional & scientific | 2020 |
| Supreme Pest Control Specialists LP | | 2015 |
| Supreme Pet Food Holdings Limited | Administrative & support | 2007 |
| Supreme Petfoods Limited | Manufacturing | 1981 |
| Sura VIP Barbers Ltd | Other services | 2026 |
| Sure Betts HR Solutions Ltd | Professional & scientific | 2021 |
| Sure Biotechnology Limited | Professional & scientific | 2008 |
| Surechem Products (Holdings) Limited | Real estate | 1996 |
| Surechem Products Limited | Wholesale & retail | 1984 |
| Surehill Limited | Real estate | 2014 |
| Surelec Electrical Ltd | Construction | 2016 |
| Suresend Ltd. | Transport & logistics | 2025 |
| Surestart Homes Ltd | Real estate | 2015 |
| Surreal Galaxy Limited | Wholesale & retail | 2025 |
| Surrey Bathrooms & Plumbing Ltd | Construction | 2022 |
| Survatec Limited | Professional & scientific | 2004 |
| Survival Instinct - Preparedness Ltd | Wholesale & retail | 2022 |
| Sustainable Synergies (Holdings) Ltd | Financial services | 2026 |
| Sustainable Synergies Ltd | Information & communication | 2025 |
| Sustainify Solutions Limited | Wholesale & retail | 2025 |
| Sustainomics Holdings Limited | Construction | 2018 |
| Sustainomics Limited | Administrative & support | 2015 |
| Sutton Business Limited | Transport & logistics | 2020 |
| Sutton Heights Management Limited | Real estate | 2004 |
| Sutton Sporting Club Limited | Arts & recreation | 2023 |
| Suttons Consumer Products Limited | Wholesale & retail | 1934 |
| Suttons Seeds Limited | Professional & scientific | 2014 |
| Suttony Projects Limited | Construction | 2023 |
| Suzanne Lock Business Services Limited | Professional & scientific | 2010 |
| Svenskhomes Developments Limited | Construction | 2014 |
| SVT Builders Ltd | Construction | 2021 |
| SW & KB Enterprises Limited | Information & communication | 2025 |