| Suds (Swindon) Limited | Wholesale & retail | 2012 |
| SUE Day Performing Arts LLP | | 2022 |
| Sugar Shack Swindon Ltd | Hospitality | 2020 |
| Sugavi Petrol Three Ltd | Wholesale & retail | 2025 |
| Sugavi Petrolium Ltd | Wholesale & retail | 2022 |
| SUK88 Consulting Ltd | Professional & scientific | 2026 |
| SUKTHI79 Ltd | Other services | 2019 |
| Sulaymaniyah Super Market Ltd | Wholesale & retail | 2020 |
| Sulemani 2 Quality Foods Ltd | Wholesale & retail | 2025 |
| Sulnad Ltd | Extraterritorial | 2023 |
| Sultan Vapes Ltd | Wholesale & retail | 2018 |
| Sum.It Consulting (UK) Ltd | Information & communication | 1999 |
| Suman Cleaning Services Swindon Ltd | Administrative & support | 2024 |
| Sumanu Limited | Real estate | 2025 |
| Summer Isles Enterprises Limited | Hospitality | 2010 |
| Summers Wellbeing Ltd | Health & social care | 2021 |
| Summit Bridge Trading Ltd | Wholesale & retail | 2025 |
| Summit Capital Investment Ltd | Professional & scientific | 2024 |
| Summit Digital Media Limited | Professional & scientific | 2024 |
| Summit Property Solutions Group Ltd | Construction | 2025 |
| Sumos Limited | Wholesale & retail | 2002 |
| Sun Design & Consultancy Limited | Professional & scientific | 2009 |
| Sun Dial Traders Limited | Manufacturing | 2023 |
| SUN13 Ltd | Construction | 2026 |
| SUN888 Limited | Hospitality | 2022 |
| Sunbase Limited | Manufacturing | 1986 |
| Sunbrooke Estates Limited | Other services | 2001 |
| Sunderland Property Management Services Limited | Real estate | 2017 |
| Sungate Travel Ltd | Administrative & support | 2025 |
| Sungh Limited | Households | 2020 |
| Sunlab.Co Limited | Other services | 2026 |
| Sunrise Housing Ltd | Real estate | 2023 |
| Sunrise Nursery School Ltd | Education | 1998 |
| Sunrise Property Maintenance Ltd | Construction | 2018 |
| Sunrise Tech Ltd | Information & communication | 2021 |
| Sunshine Maids Cleaning Services Ltd | Administrative & support | 2024 |
| Sunshine Properties Swindon Limited | Real estate | 2021 |
| Sunshine Transport and Logistics Ltd | Transport & logistics | 2026 |
| Sunshine Unique Designs Limited | Wholesale & retail | 2023 |
| Sunsol Group Limited | Manufacturing | 1987 |
| Suntasy Ltd | Wholesale & retail | 2025 |
| Suntome Ltd | Professional & scientific | 2026 |
| Sunwar Ltd | Manufacturing | 2026 |
| Super Juicy Vapes Ltd | Wholesale & retail | 2020 |
| Superb Moves Ltd. | Transport & logistics | 2017 |
| Supercharged Ltd | Information & communication | 2025 |
| Superglide Wardrobes Limited | Manufacturing | 2012 |
| Superitskills Limited | Information & communication | 2023 |
| Supermarine Sports Club (Trading) Limited | Arts & recreation | 2015 |
| Supermarine Sports Club Limited | Arts & recreation | 2011 |
| Superpow (Spuk) Limited | Financial services | 2020 |
| Supply Chain Excellence Limited | Professional & scientific | 2001 |
| Support-Options Limited | Health & social care | 2017 |
| Supportability Engineering for Defence Ltd | Public administration | 2008 |
| Supreme Contract Services Limited | Administrative & support | 2013 |
| Supreme Image Windows Limited | Construction | 2023 |
| Supreme Painting & Decorating Limited | Construction | 2024 |
| Supreme Provider Enterprise Limited | Health & social care | 2015 |
| Supreme Tyre Swindon Ltd | Wholesale & retail | 2024 |
| Suraj Sanapathi Limited | Wholesale & retail | 2025 |
| Sure Plugs Ltd | Construction | 2024 |
| Sure Recruitment Agency Ltd | Administrative & support | 2018 |
| Sure Travel Limited | Transport & logistics | 2024 |
| Surefit Specialists Limited | Construction | 2012 |
| Surefit Windows Limited | Construction | 2003 |
| Surehome Construction Limited | Construction | 1992 |
| Sureplumb Plumbing & Heating Limited | Construction | 2012 |
| Surface Systems (Coatings) Limited | Construction | 2005 |
| Surrendell Surgery Limited | Health & social care | 2019 |
| Surveying Xperts Ltd | Other services | 2024 |
| Survivor@Swa Limited | Wholesale & retail | 2019 |
| Susanmercy Healthcare Limited | Public administration | 2019 |
| Susanu Limited | Transport & logistics | 2019 |
| Sushi Redruth Ltd | Hospitality | 2026 |
| Susie Magill LLP | | 2022 |
| Susman Trans Ltd | Administrative & support | 2016 |
| Sussex Place Kebab Van Ltd | Hospitality | 2026 |
| Sussex Stationers Limited | Extraterritorial | 2011 |
| Sustain Operations Community Interest Company | Agriculture & fishing | 2025 |
| Sustain Security Services Limited | Administrative & support | 2019 |
| Sustain Wiltshire Limited | Agriculture & fishing | 2022 |
| Sustainable Planet Solutions Limited | Agriculture & fishing | 2024 |
| Sustaining Futures Limited | Professional & scientific | 2018 |
| Suton Limited | Professional & scientific | 2010 |
| Sutton Matthews Holdings Ltd | Real estate | 2021 |
| Suzie Hawkins NMP Ltd | Health & social care | 2025 |
| SV Mintey Ltd | Real estate | 2021 |
| SVA Transport Ltd | Transport & logistics | 2022 |
| SVB Services Limited | | 2006 |
| Sven Dental Ltd | Health & social care | 2024 |
| Svensoni Paraplanning Limited | Administrative & support | 2013 |
| SVN Trans Limited | Transport & logistics | 2017 |
| SW Joinery Ltd | Manufacturing | 2019 |
| SW Paving Limited | Construction | 2015 |
| Swami Shree JI Properties Limited | Real estate | 2024 |
| Swan Counselling CIC | Health & social care | 2025 |
| Swan Laundry Swindon Ltd | Other services | 2023 |
| Swanhill Consulting Ltd | Information & communication | 2026 |
| Swedish Office Ltd | Information & communication | 2026 |
| Sweet Briar Court Management Limited | Households | 1991 |