| RJ Operations Ltd | Financial services | 2022 |
| RJS Operations Limited | Financial services | 2019 |
| RJW Developments Ltd | Real estate | 2004 |
| RM Steel Erection Limited | Construction | 2007 |
| RMG Haulage Services Limited | Transport & logistics | 2019 |
| RMS Aluminium Systems Ltd | Construction | 2019 |
| Roadhead Farm Feeds Ltd | Manufacturing | 2004 |
| Roadright Limited | Wholesale & retail | 2019 |
| Roanne Transport Ltd | Transport & logistics | 2019 |
| Robert Brown Architectural Solutions Ltd | Professional & scientific | 2007 |
| Robert Dickie and Sons, Limited | Real estate | 1950 |
| Rockspring Properties Limited | Real estate | 2006 |
| Rockview Engineers Limited | Construction | 2020 |
| Rockview Plumbing & Heating Limited | Construction | 2020 |
| Rodina Foods Ltd | Hospitality | 2020 |
| Rogers Opex Consulting Limited | Professional & scientific | 2012 |
| Roguery Road Ltd | Construction | 2026 |
| Rojo Enterprises Limited | Real estate | 2013 |
| Roofresh NI Ltd | Administrative & support | 2022 |
| Roofscape Group Limited | Real estate | 2018 |
| Rooney Developments Limited | Hospitality | 1995 |
| Root and River Co Limited | Professional & scientific | 2025 |
| Rope Access Specialists Limited | Other services | 2000 |
| ROS 1 Trading Limited | Wholesale & retail | 2016 |
| Rosa Healthcare Limited | Health & social care | 2024 |
| Rosa Properties Limited | Real estate | 2024 |
| Rosanagh Services Ltd | Professional & scientific | 2021 |
| Roscarrig Residents Management Company Ltd | Households | 2014 |
| Rose Studio Ireland Ltd | Wholesale & retail | 2025 |
| Roslea Enterprises Ltd | Real estate | 1990 |
| Roslea Oils Limited | Manufacturing | 2015 |
| Rosscairn Farms Ltd | Agriculture & fishing | 2011 |
| Rossclare Properties Limited | Real estate | 2006 |
| Rosscolban 12 Limited | Real estate | 2012 |
| Rossharbour Resort Limited | Hospitality | 2018 |
| Rossmacole Ltd | Real estate | 2021 |
| Rossmore Enterprises Limited | Hospitality | 2017 |
| Rossorry Court Management Limited | Real estate | 2004 |
| Rossory Management Company Limited | Households | 2020 |
| Roundshore Properties Limited | Wholesale & retail | 1991 |
| Rowan Tree Lane Limited | Information & communication | 2012 |
| Royston Properties Limited | Real estate | 1998 |
| RPK Plumbing & Mechanical Services Limited | Construction | 2024 |
| RPM Solutions Ltd | Other services | 2020 |
| Rr&Cc NOS Parts Limited | Wholesale & retail | 2023 |
| Ruby Palace Restaurant Ltd | Hospitality | 2025 |
| RUH Imports Ltd | Wholesale & retail | 2025 |
| Rushin House Limited | Hospitality | 2019 |
| RV Eggs Limited | Wholesale & retail | 2023 |
| Ryan Mcgorman Limited | Agriculture & fishing | 2018 |
| Rycon Construction Limited | Administrative & support | 2014 |
| S & E B Holdings Limited | Financial services | 2022 |
| S & G Fitness Hub Ltd | Arts & recreation | 2025 |
| S C Haulage Ltd | Transport & logistics | 2019 |
| S G Agents (NI) Limited | Administrative & support | 2012 |
| S Graham BUS Hire Ltd | Transport & logistics | 2026 |
| S Graham Properties Limited | Construction | 2024 |
| S K MCD Properties Limited | Real estate | 2025 |
| S Mcquade & SON Utilities Ltd | Construction | 2019 |
| S.L.C.M.S.S Ltd | Manufacturing | 2014 |
| S.Mag Electrics Ltd | Construction | 2015 |
| SA MED AID Limited | Health & social care | 2026 |
| Safe Haven Opportunities Ltd | Health & social care | 2016 |
| Salt Range Ltd | Hospitality | 2020 |
| Salus Training Academy Ltd | Education | 2024 |
| Samaca Trading Ltd | Wholesale & retail | 2024 |
| Samdec Ltd | Wholesale & retail | 2003 |
| Sandy Lane Management Company (Enniskillen) Ltd | Administrative & support | 2007 |
| Sarcon (NO.39) Limited | Manufacturing | 1996 |
| Save OUR Services S.W.A.H. CIC | Health & social care | 2023 |
| Savoury Foods Enniskillen Limited | Hospitality | 2014 |
| Savoury Foods Limited | Hospitality | 2014 |
| SB Construction Limited | Professional & scientific | 2020 |
| SC Wood Chipping Ltd | Agriculture & fishing | 2025 |
| Scaff Tech Solutions UK Limited | Construction | 2024 |
| Scaff World UK Limited | Construction | 2024 |
| Scaffweld Limited | Construction | 2026 |
| Scallon Electrics Ltd | Construction | 2019 |
| Scar Systems Limited | Extraterritorial | 1996 |
| SCH Construction Limited | Construction | 2014 |
| SCH Truck Rental Limited | Administrative & support | 2022 |
| Schultz Fertility Limited | Manufacturing | 2025 |
| Scollan Plastering Ltd | Construction | 2022 |
| Scott's Irish Distillery Limited | Manufacturing | 2019 |
| Sculptic Clinic Ltd | Other services | 2019 |
| SD Agri Ltd | Wholesale & retail | 2020 |
| Seamus Stewart Electrical Limited | Construction | 2003 |
| Sean Clear Ltd | Hospitality | 2019 |
| Sean Timoney & Sons Limited | Manufacturing | 1999 |
| Sega Holdings Ltd | Financial services | 2025 |
| Senhora DA Rocha Holdings Ltd | Financial services | 2025 |
| Setanta Pharmaceuticals Ltd | Wholesale & retail | 2024 |
| Setanta Protection Services Ltd | Administrative & support | 2024 |
| Sfmce Limited | Construction | 2018 |
| Sgoodall Ltd | Professional & scientific | 2025 |
| Shadesofamaezin Ltd | Construction | 2023 |
| Shannagh Properties Limited | Real estate | 2015 |
| Shanra Eggs Limited | Wholesale & retail | 2019 |
| Share Discovery Village | Health & social care | 1977 |
| Sharing of Ministries Abroad Ireland | Information & communication | 2018 |