| Scutch and Soda Ltd | Hospitality | 2019 |
| SD Art Holdings Ltd | Financial services | 2018 |
| SD Global Solutions Limited | Manufacturing | 2020 |
| Sealawal Ltd | Wholesale & retail | 2026 |
| Sean Casey Ltd | Wholesale & retail | 2025 |
| Sean Rice Ltd | Wholesale & retail | 2025 |
| Seapark Construction (Holywood) Limited | Construction | 2013 |
| Seaward Investments (NO. 2) Ltd | Real estate | 2023 |
| Secondary Glazing Belfast Limited | Construction | 2024 |
| Secrets of Salem Ltd | Wholesale & retail | 2024 |
| Secure Optical Network Communications Limited | Information & communication | 2002 |
| Securebox Storage Limited | Transport & logistics | 2024 |
| Seed Invest Ltd | Real estate | 2020 |
| Seeed Development Limited | Manufacturing | 2024 |
| Seek Property Limited | Real estate | 2022 |
| Segen Synergies Ltd | Professional & scientific | 2025 |
| Segura Contracts Ltd | Construction | 2026 |
| Select Brokers Ltd | Financial services | 2016 |
| Select Mortgage & Financial Solutions Ltd | Administrative & support | 2004 |
| Selfserve Limited | Extraterritorial | 2010 |
| Sellingwithjoy LP | | 2020 |
| Sensotech Technology Limited | Wholesale & retail | 2025 |
| Seraphim Properties Ltd | Real estate | 2022 |
| Serious Tiling Limited | Construction | 2024 |
| Sermet (Northern Ireland) Limited | Wholesale & retail | 1975 |
| Servd PTY Limited | Wholesale & retail | 2025 |
| Seth Properties Limited | Real estate | 2001 |
| Settled Petals Limited | Education | 2025 |
| SEVEN7INVESTMENTS Ltd | Real estate | 2021 |
| SEVEN7LBR Ltd | Hospitality | 2019 |
| SEVEN7SOCIAL Ltd | Real estate | 2019 |
| SEVEN7STAYS Ltd | Hospitality | 2017 |
| SEW Ready CIC | Manufacturing | 2022 |
| Seymour Construction (N.I.) Ltd | Construction | 2018 |
| SG Fitout Ltd | Manufacturing | 2016 |
| SGR Properties Limited | Real estate | 2014 |
| Sgsp Ltd | Financial services | 2024 |
| Shacro Contracts Limited | Construction | 2021 |
| Shane Niblock Investments Ltd | Real estate | 2022 |
| Sharma Diagnostics Limited | Health & social care | 2025 |
| Sharon Murray Limited | Administrative & support | 2021 |
| Sharp (N.I.) Ltd | Hospitality | 2012 |
| Sharper Solutions Ltd | Administrative & support | 2026 |
| Shay Casey Ltd | Wholesale & retail | 2025 |
| Shellard Tiles Ltd | Construction | 2020 |
| Shelton U.K. Limited | Wholesale & retail | 2020 |
| Sherwood & Lynas Limited | Real estate | 2024 |
| Shine Professional Cleaning Services Ltd | Administrative & support | 2020 |
| Shining Light Sport Limited | Education | 2015 |
| Shirping World Resources Limited | Arts & recreation | 2015 |
| Shni Limited | Construction | 2023 |
| Shop Commerce LP | | 2018 |
| Shopmobility Lisburn | Other services | 2000 |
| Short Stay N.I. Ltd | Real estate | 2022 |
| Showcase Property Staging NI Ltd | Professional & scientific | 2025 |
| Sight Loss Ministries Limited | Other services | 2021 |
| Silk Sales LP | | 2022 |
| Simon Reid Electrical Services Ltd | Manufacturing | 2025 |
| Simple Business Telecoms Ltd | Information & communication | 2015 |
| Simple Green Limited | Information & communication | 2020 |
| Simply Lisburn Ltd | Hospitality | 2025 |
| SIN É Props Ltd | Information & communication | 2023 |
| Sinosky Limited | Manufacturing | 2024 |
| SIR Trees Ltd | Agriculture & fishing | 2026 |
| Sitc Belfast Limited | Hospitality | 2012 |
| Sixyard Analytics Ltd | Professional & scientific | 2025 |
| SJ Car Body Repairs Ltd | Wholesale & retail | 2018 |
| SJS Tiling & Bathrooms Ltd | Construction | 2024 |
| SJS Tiling (N.I.) Ltd | Construction | 2019 |
| SK Ballyclare Limited | Hospitality | 2018 |
| Skidata Ireland Ltd. | Construction | 1999 |
| Skin . Beauty Clinic Ltd | Other services | 2022 |
| Skinovation Enterprises Ltd | Wholesale & retail | 2023 |
| Skippy Spares Limited | Wholesale & retail | 2018 |
| Sknrgy Ltd | Other services | 2025 |
| Skrej Ltd | Real estate | 2026 |
| Sky Business Consultants Limited | Professional & scientific | 2020 |
| Skyn Boutique Limited | Other services | 2017 |
| Slabbed Crusaders Ltd | Wholesale & retail | 2022 |
| Slipstream Software Limited | Administrative & support | 2022 |
| SLN Performance Ltd | Wholesale & retail | 2021 |
| Sloan Construction Ltd | Construction | 2024 |
| Sloan Engineering Ltd | Manufacturing | 2022 |
| Sloan Plumbing Ltd | Construction | 2025 |
| SM Construction 2010 Ltd | Construction | 2023 |
| Smart Aesthetics Ltd | Health & social care | 2023 |
| Smart Monitoring Control Systems Ltd | Professional & scientific | 2017 |
| Smart Space Logistics Ltd | Transport & logistics | 2020 |
| Smart Space Storage Ltd | Transport & logistics | 2018 |
| Smartbee Experts LP | | 2021 |
| Smartrf Ltd | Information & communication | 2009 |
| SMC Optical Ltd | Health & social care | 2024 |
| SMG Equity Ltd | Real estate | 2014 |
| SMG Properties Limited | Real estate | 2004 |
| Smiley Monroe Holdings Limited | Real estate | 2002 |
| Smiley Monroe Limited | Manufacturing | 1986 |
| Smitty Enterprises Ltd | Wholesale & retail | 2024 |
| SML Reporting Ltd | Health & social care | 2024 |
| Smoff IT Consultancy Limited | Information & communication | 2025 |
| SMS Partnership Ltd | Professional & scientific | 2008 |