| Rockmount Farms Ltd | Agriculture & fishing | 2016 |
| Rockmount Recycling Ltd | Water & waste | 2024 |
| Rocksalt Kitchen & Bar Ltd | Hospitality | 2026 |
| Rockvale Potato Products Ltd | Manufacturing | 2020 |
| Rocneh Ltd | Construction | 1971 |
| Rodger Neilly Landscape Design Ltd | Administrative & support | 2020 |
| Rogan Accountancy Limited | Professional & scientific | 2014 |
| Rollins Promotions Limited | Manufacturing | 1986 |
| Rollnrug Ltd | Wholesale & retail | 2025 |
| Romen Words Ltd | Wholesale & retail | 2024 |
| Rosecliff Developments Ltd | Wholesale & retail | 2025 |
| Rosepark Estates Ltd | Real estate | 2013 |
| Roskyle Limited | Construction | 1989 |
| Roskyle Plant Hire Limited | Administrative & support | 2017 |
| Roun Yanre Limited | Wholesale & retail | 2025 |
| Route Strategies Limited | Wholesale & retail | 2025 |
| Rowley Leisure Parks Limited | Professional & scientific | 2002 |
| Rowreagh Farm Limited | Agriculture & fishing | 1996 |
| ROY Lyttle Limited | Agriculture & fishing | 2004 |
| RPM Auto Keys Ltd | Manufacturing | 2022 |
| Rras (NI) Limited | Professional & scientific | 2017 |
| Rubane Leisure Ltd | Wholesale & retail | 2013 |
| Ruddell Metals | Administrative & support | 2002 |
| Ruilideretai Ltd | Wholesale & retail | 2025 |
| Ruiliyayabgretail Limited | Wholesale & retail | 2025 |
| Russell & Co. (NO.1) Limited | Professional & scientific | 2012 |
| Russell & Co. Limited | Professional & scientific | 2023 |
| Russell Property Agents Limited | Real estate | 2025 |
| RW Powder Coatings Limited | Manufacturing | 2010 |
| Rybob Ltd | Manufacturing | 2024 |
| Rymont Ecology Ltd | Professional & scientific | 2025 |
| S & R Toan Ltd | Construction | 2008 |
| S C Newsagents Ltd | Wholesale & retail | 2006 |
| S Clarke and SON Memorial Reserve Trust | Professional & scientific | 2024 |
| S D Mccullough Contracts Ltd | Construction | 2014 |
| S Mayne Consulting Ltd | Professional & scientific | 2021 |
| S Mcveigh Ltd | Manufacturing | 2026 |
| S Scott & SON Ltd | Construction | 2004 |
| S Sheals & SON Limited | Manufacturing | 2015 |
| Sabichi Homewares NI Ltd | Wholesale & retail | 2023 |
| Sacred Oak Spirits Limited | Manufacturing | 2025 |
| Saddlery Student Ltd | Manufacturing | 2017 |
| Safetan Limited | Other services | 1992 |
| Saints Cafe Ltd | Hospitality | 2022 |
| Salmon Property Holdings Ltd | Real estate | 2025 |
| Salt 'N' Vinegar (Bangor) Ltd | Hospitality | 2021 |
| Salt 'N' Vinegar Newtownards Ltd | Hospitality | 2024 |
| Saltwater Mills Ltd | Construction | 1999 |
| SAM Wlsn Ltd | Information & communication | 2021 |
| SAM Wolsey Photography Ltd | Professional & scientific | 2018 |
| Sam's Appliance Rentals Limited | Administrative & support | 2019 |
| Sam's Rentals Limited | Administrative & support | 2022 |
| Sam's Washing Machine Rentals Limited | Administrative & support | 2020 |
| Samchris Consultants Limited | Administrative & support | 1999 |
| Samuel Crawford Ltd | Wholesale & retail | 2024 |
| Samuel Duffin Limited | Real estate | 1928 |
| Sancta Maria Fisheries Ltd | Agriculture & fishing | 2018 |
| Sandycove Holiday Homes Ltd | Hospitality | 1995 |
| Sanyx International Ltd | Information & communication | 2006 |
| Sarah ORN Limited | Wholesale & retail | 2024 |
| Sarahjl Ltd | Wholesale & retail | 2025 |
| Sarayu Property Ltd | Hospitality | 2022 |
| Sathit Aswa Ltd | Wholesale & retail | 2024 |
| Sauncaideretail Ltd | Wholesale & retail | 2024 |
| Saunders Trading Solutions Ltd | Extraterritorial | 2022 |
| Sayhey Free Ltd | Wholesale & retail | 2024 |
| Sayoulala Limited | Wholesale & retail | 2024 |
| Sbjj Ltd | Education | 2023 |
| SC Rowe Investments Ltd | Real estate | 2026 |
| Scent Instructors Network Limited | Education | 2025 |
| School's OUT N.I. Limited | Health & social care | 2025 |
| Schuco GmbH Limited | Wholesale & retail | 2025 |
| Scioto Limited | Information & communication | 2008 |
| Scni Servicing Ltd | Other services | 2024 |
| Score Draw Digs Ltd | Real estate | 2020 |
| Score Draw Music Limited | Information & communication | 2010 |
| Scott Bowman Haulage Ltd | Transport & logistics | 2024 |
| Scott Civil Engineering Ltd | Professional & scientific | 2015 |
| Scott Iyas Ltd | Wholesale & retail | 2024 |
| Scott Ktai Limited | Wholesale & retail | 2025 |
| Scrabo Alternative Energy Ltd | Energy | 2015 |
| Scrabo Consulting Limited | Extraterritorial | 2014 |
| Scrabo Dansard Limited | Real estate | 2022 |
| Scrabo Enterprises Limited | Extraterritorial | 2014 |
| Scrabo IT Limited | Extraterritorial | 2014 |
| Scrabo Kitchens Ltd | Manufacturing | 2022 |
| Scrabo Property Limited | Real estate | 2018 |
| Scrabo Road Management Company Limited | Households | 2020 |
| Scree Crest Limited | Wholesale & retail | 2025 |
| Sculpt Revolution Ltd | Education | 2025 |
| SDM Residential Ltd | Real estate | 2026 |
| Sea WJ Limited | Wholesale & retail | 2024 |
| Seamus Owens Ltd | Wholesale & retail | 2025 |
| Secure Vision Systems Limited | Administrative & support | 2002 |
| Seed-Seek Tech Ltd | Wholesale & retail | 2024 |
| Seesports Ltd | Administrative & support | 2011 |
| Serendipity Cat Ltd | Wholesale & retail | 2025 |
| Serenity Care N.I. Limited | Health & social care | 2025 |
| Service Care D.A.R. Ltd | Manufacturing | 2010 |
| SES Electrical (N.I.) Ltd | Construction | 2012 |