| SW Equine Limited | Agriculture & fishing | 2015 |
| Swadesh Prem Ltd | Health & social care | 2020 |
| Swallow Construction Ltd | Construction | 2021 |
| Swallow Games Ltd. | Wholesale & retail | 2000 |
| Swallow Marketing Communications Limited | Professional & scientific | 2013 |
| Swallow Properties (EN) Ltd | Real estate | 2017 |
| Swan & Joy Ltd | Real estate | 2024 |
| Swan & Joy Property Ltd | Real estate | 2024 |
| Swanblack Ltd | Administrative & support | 2025 |
| Swans Brook (Abberton) Management Company Limited | Households | 2026 |
| Swanton Vale (Swanton Morley) Management Company Limited | Households | 2021 |
| Swarzy Cleaning Limited | Administrative & support | 2018 |
| Swattesfield Campsite Limited | Hospitality | 2016 |
| Sweet AS Media Ltd | Information & communication | 2009 |
| Sweets N Stuff LP | | 2021 |
| Swenscape Limited | Wholesale & retail | 2026 |
| Swiddie Limited | Real estate | 2025 |
| Swift Assist Services Ltd | Administrative & support | 2025 |
| Swiftcrest Transport Ltd | Extraterritorial | 2026 |
| Swiftpeak Solutions Ltd | Wholesale & retail | 2025 |
| Swilland Manor Enterprises Limited | Real estate | 2003 |
| Swim at the Mill Ltd | Arts & recreation | 2017 |
| Swimstrength Ltd | Education | 2024 |
| Swing Leisure Ltd | Arts & recreation | 2025 |
| Swiskar Ltd | Wholesale & retail | 2017 |
| Switch Direction Group Ltd | Education | 2025 |
| Switched on (International) | Other services | 2006 |
| Swml Limited | Administrative & support | 2012 |
| Swordschool Ltd. | Arts & recreation | 2016 |
| SWS Consultancy Limited | Administrative & support | 2014 |
| Swym Events Limited | Arts & recreation | 2024 |
| Sycamore Holdings 2026 Ltd | Financial services | 2026 |
| Syls & Graces Ltd | Health & social care | 2017 |
| Sym's Pantry Limited | Hospitality | 2017 |
| Symbiosis Lighting Limited | Information & communication | 2012 |
| Symbiotic Solutions Limited | Water & waste | 2008 |
| Sympathetic Restorations Limited | Information & communication | 2008 |
| Symsol Holdings Ltd | Financial services | 2021 |
| Symtote Ltd | Professional & scientific | 2025 |
| SYN PVT. Ltd | Real estate | 2025 |
| Synapse Investments Ltd | Real estate | 2024 |
| Syndicate Productions Ltd | Other services | 2021 |
| Synergy Container Logistics Ltd | Transport & logistics | 2025 |
| Synergy Integrated Systems Limited | Information & communication | 2005 |
| Synergy Resourcing Solutions Limited | Administrative & support | 2023 |
| Synetos Ltd | Professional & scientific | 2024 |
| Synolo Design Ltd | Professional & scientific | 2014 |
| Synphonica Ltd | Information & communication | 2024 |
| Synthetix Visionaries Ltd | Professional & scientific | 2024 |
| Syon Grove Projects Ltd | Real estate | 2025 |
| Sysmedia Limited | Information & communication | 1998 |
| System 72 Ltd | Professional & scientific | 2024 |
| Systematic Reviews Ltd | Professional & scientific | 2025 |
| Sytteb Virtual Limited | Education | 2021 |
| SZB Services Ltd | Transport & logistics | 2025 |
| Szucs Trans Ltd | Transport & logistics | 2024 |
| T & E Suffolk Construction Ltd | Construction | 2017 |
| T & L Banks Ltd | Construction | 2018 |
| T & M Carpentry Limited | Construction | 2005 |
| T & P Lait LLP | | 2015 |
| T & R Engineering Ltd | Professional & scientific | 2015 |
| T a B Engineering Limited | Manufacturing | 2001 |
| T Ahmed Property Management Limited | Wholesale & retail | 2024 |
| T C Patmore Water Softeners Limited | Wholesale & retail | 2003 |
| T D Gray Limited | Professional & scientific | 2001 |
| T H & M Ltd | Agriculture & fishing | 2021 |
| T Hally Trans Ltd | Transport & logistics | 2020 |
| T J Construction & Renovation Limited | Construction | 2003 |
| T J Construction (East Anglia) Limited | Real estate | 2010 |
| T L C Properties (Suffolk) Limited | Administrative & support | 2017 |
| T L Chimneys Limited | Administrative & support | 2014 |
| T Line Roofing & Guttering Ltd | Construction | 2025 |
| T M & Co Partners Limited | Wholesale & retail | 2024 |
| T Matulis Ltd | Construction | 2024 |
| T R Bickers Management Limited | Extraterritorial | 2015 |
| T S Property Services Limited | Construction | 2003 |
| T&A Nail Spa Ltd | Other services | 2025 |
| T&B Design Ltd | Professional & scientific | 2023 |
| T&J Management Ltd | Administrative & support | 2020 |
| T&L Group Limited | Other services | 2016 |
| T&M Builders Suffolk Ltd | Construction | 2023 |
| T&M Courier Ltd | Construction | 2023 |
| T&M SF Holdings Limited | Financial services | 2023 |
| T&M Topco Limited | Professional & scientific | 2021 |
| T.A.K. Building Maintenance Ltd | Construction | 2010 |
| T.C Aerials Digital Aerial Specialists Limited | Other services | 1998 |
| T.C. Barber Shop Ltd | Other services | 2013 |
| T.E.W. Solicitors Limited | Professional & scientific | 2016 |
| T.H. Moss and Sons Limited | Administrative & support | 1985 |
| T.H.E Data Associates Ltd. | Information & communication | 2016 |
| T.J. Wheaton Limited | Agriculture & fishing | 1997 |
| T.M Electrical Solutions Ltd | Construction | 2014 |
| T.M Garden Masters Ltd | Administrative & support | 2025 |
| T1 Coaching Limited | Education | 2023 |
| T1 Medical Solutions Limited | Health & social care | 2025 |
| T2 Collective Ltd | Professional & scientific | 2025 |
| TA Online Retail Ltd | Wholesale & retail | 2026 |
| TA Property Maintenance Limited | Construction | 2023 |
| TA Security Ltd | Administrative & support | 2013 |
| TAB Professional Property Services Ltd | Construction | 2015 |