| Sempasco Ltd | Construction | 2024 |
| Semvar Ltd | Information & communication | 2021 |
| Servall Solutions Limited | Administrative & support | 2017 |
| Service Networks Ltd | Professional & scientific | 2023 |
| Sewing Mills Ltd | Manufacturing | 2022 |
| Shantallow Renewal Company | Other services | 2020 |
| Sharagore Homes Limited | Construction | 2024 |
| Shaun Doherty Developments Limited | Construction | 2016 |
| Shaun Mcateer & Co. Ltd | Professional & scientific | 2009 |
| Sheephaven Farm Limited | Agriculture & fishing | 2019 |
| Sheils Boyle HR Associates Ltd | Administrative & support | 2026 |
| Shejmz Limited | Financial services | 2021 |
| Shining Light Music Limited | Arts & recreation | 2024 |
| Shipquay Holdings Limited | Financial services | 2026 |
| Shipquay Hotel Ltd | Hospitality | 2017 |
| Shoreline Factors Ltd. | Arts & recreation | 2012 |
| Short.Rentals Ltd | Hospitality | 2020 |
| Short.Visits Ltd | Hospitality | 2020 |
| Silverhill Contracts Ltd. | Construction | 2017 |
| Sinnsro Ltd | Hospitality | 2024 |
| SIR LAD Properties Ltd | Real estate | 2024 |
| Sjfp Electrical Ltd | Professional & scientific | 2024 |
| Skill School Ltd | Arts & recreation | 2016 |
| Skip Design Ltd | Professional & scientific | 2004 |
| SL UMI Ltd | Hospitality | 2022 |
| Sleepladder Limited | Wholesale & retail | 2018 |
| Smart Mortgages Limited | Financial services | 2016 |
| Smartegic Consulting Limited | Professional & scientific | 2020 |
| Smarteposni Ltd | Wholesale & retail | 2021 |
| Smartpayni Limited | Administrative & support | 2017 |
| SMC Agricultural Contractors Ltd | Administrative & support | 2025 |
| SMD Electrical Compliance Limited | Construction | 2026 |
| SMD Tech Ltd | Administrative & support | 2025 |
| Smera Limited | Health & social care | 2017 |
| Smera Properties Ltd | Real estate | 2023 |
| SMG Financial Services Ltd | Financial services | 2013 |
| SMG Worldwide Ltd | Other services | 2012 |
| SML Mechanical Engineering Ltd | Professional & scientific | 2026 |
| Smokeless Coal Express Limited | Wholesale & retail | 2023 |
| SMV Ventilation Limited | Manufacturing | 2018 |
| Snaidhmthe Ltd | Professional & scientific | 2023 |
| Softdecks Ltd | Manufacturing | 2023 |
| Sojourne Limited | Wholesale & retail | 2016 |
| Solar Performance Ireland LLP | | 2024 |
| Sole Purpose | Arts & recreation | 1999 |
| Source FM Limited | Professional & scientific | 2010 |
| Souvenir Supplies Ireland Ltd | Wholesale & retail | 2024 |
| SPC Care Ltd | Other services | 2016 |
| SPC Care Property Ltd | Real estate | 2026 |
| Specialist Fleet Sales Ltd | Wholesale & retail | 2025 |
| Spencer RD Ltd | Hospitality | 2020 |
| Sperrin Lands Limited | Wholesale & retail | 2014 |
| Sportique Sportswear Limited | Wholesale & retail | 2002 |
| Springrowth Landscape and Garden Centre Limited | Wholesale & retail | 2020 |
| SR Advanced Energies Limited | Wholesale & retail | 2022 |
| SSE Service (IRE) Ltd | Manufacturing | 2011 |
| ST Columb's Hall Trust | Arts & recreation | 2019 |
| ST Mary's Youth Club Ltd | Other services | 2022 |
| ST. Bridget's Community Bingo Ltd | Arts & recreation | 2017 |
| Star Bingo Limited | Arts & recreation | 1998 |
| Star Snooker Limited | Arts & recreation | 1998 |
| Step Ahead Orthopaedics Limited | Health & social care | 2026 |
| Stephanie Martin Consultancy Limited | Health & social care | 2011 |
| Stephen Murray Tiles Limited | Construction | 2025 |
| Steve Reid Construction Ltd | Construction | 2024 |
| Stevenson's Kitchens & Bedrooms Limited | Manufacturing | 2001 |
| Stewart Avodah NI Ltd | Wholesale & retail | 2023 |
| Stoneywood Property Ltd | Real estate | 2022 |
| Storm Media Advertising Ltd | Professional & scientific | 2022 |
| Story Junction Limited | Other services | 2015 |
| STRAND.4 Ltd | Real estate | 2016 |
| Strathfoyle Village Centre Limited | Real estate | 2001 |
| Stretech Ltd | Construction | 2025 |
| Strive Performance Centre Limited | Arts & recreation | 2024 |
| Suede Hair and Beauty Ltd | Other services | 2019 |
| Sultan Developments Limited | Real estate | 2007 |
| Superior VC Limited | Wholesale & retail | 2018 |
| Supervalu Shantallow Ltd | Wholesale & retail | 2023 |
| Surefire Collective Ltd | Wholesale & retail | 2026 |
| Surestart Edenballymore | Health & social care | 2007 |
| Swilly Brickwork Limited | Construction | 2021 |
| T Doherty Consultancy Ltd | Construction | 2023 |
| T1PC Ltd | Real estate | 2019 |
| T2 Corporation Limited | Wholesale & retail | 2026 |
| Tactixs Ltd | Arts & recreation | 2025 |
| Tailte Lettings Limited | Hospitality | 2024 |
| Tailte Technologies Limited | Information & communication | 2024 |
| Tally Properties Limited | Real estate | 2011 |
| TAN ME NW Ltd | Other services | 2026 |
| Taragon Limited | Real estate | 2013 |
| Tattoo Guru Limited | Manufacturing | 2024 |
| TCC Joinery Limited | Construction | 2014 |
| TCE Enterprises Ltd | Wholesale & retail | 2009 |
| Tead EOT Limited | Financial services | 2025 |
| Teamslogo Ltd | Information & communication | 2018 |
| Technicaltea Ltd | Information & communication | 2019 |
| Teeva Limited | Administrative & support | 2022 |
| Templemore Properties (Holdings) Limited | Financial services | 2016 |
| TFP Capital Ltd | Real estate | 2024 |
| THE American Bar (Strabane) Ltd | Hospitality | 2011 |