| RAI Corp Limited | Information & communication | 2022 |
| Rainbow Rehoming Centre | Professional & scientific | 2004 |
| Rainbow Restaurant BT48 Limited | Hospitality | 2022 |
| Raiyan Smart & Tech Ltd | Wholesale & retail | 2025 |
| Rakk Group Limited | Real estate | 2019 |
| RAM Civils Ltd | Construction | 2023 |
| Rams Investments Ltd | Financial services | 2025 |
| Rankin Machine Tool Services Ltd | Manufacturing | 2006 |
| Rapid Modular Response Group Limited | Construction | 2026 |
| Rate Clever Ltd | Professional & scientific | 2025 |
| Rath Watches Ltd | Manufacturing | 2025 |
| Rathkeel Limited | Real estate | 2012 |
| RAW Fitness Derry Limited | Arts & recreation | 2021 |
| Raymond's Chinese Take Away Ltd | Hospitality | 2016 |
| Raypac Ltd | Administrative & support | 2023 |
| RB Building Assessors Ltd | Other services | 2013 |
| Rccni Limited | Other services | 2025 |
| Rcgr Group Ltd | Wholesale & retail | 2023 |
| RCM Fleet Management Ltd | Manufacturing | 2026 |
| Rcpj Limited | Real estate | 2012 |
| RD Hospitality Ltd | Hospitality | 2025 |
| RD Online Coaching Limited | Arts & recreation | 2025 |
| Rdvc Limited | Administrative & support | 2013 |
| RE Services Ltd | Construction | 2019 |
| Reach Across | Education | 1998 |
| Real Clothing 247 Ltd | Wholesale & retail | 2024 |
| Realia Pizza Ltd | Hospitality | 2025 |
| Reality Check Media Limited | Information & communication | 2014 |
| Realtra Consulting Ltd | Information & communication | 2023 |
| Recro Properties Limited | Real estate | 2014 |
| Red Door Pastry Limited | Hospitality | 2025 |
| Red Oak Real Estate Limited | Professional & scientific | 2017 |
| Red Road Properties Limited | Extraterritorial | 2014 |
| Redemption Barbell Ltd | Arts & recreation | 2014 |
| Redmond Plastering Limited | Construction | 2017 |
| Redtop Vending Ltd | Manufacturing | 2023 |
| Redwood Trading and Consultancy Ltd | Wholesale & retail | 2013 |
| Regent House Enterprises Ltd | Construction | 2019 |
| Reggies Paw's Ltd | Wholesale & retail | 2024 |
| Reilly Properties Limited | Households | 2020 |
| Rejuvinox Ltd | Other services | 2016 |
| Reliable Transport Solutions Ltd | Agriculture & fishing | 2003 |
| Remo Pro Entertainment Holdings Ltd | Financial services | 2025 |
| Remo Records Ltd | Information & communication | 2025 |
| Rendering Services Ireland Ltd | Construction | 2024 |
| Rendering Supplies Ireland (RSI Store) Ltd | Wholesale & retail | 2020 |
| Rendo Staging Ltd | Information & communication | 2025 |
| Renested Limited | Real estate | 2025 |
| Renew Polymers Limited | Wholesale & retail | 2025 |
| Repair and Share Foyle C.I.C. | Other services | 2023 |
| Resc Properties Ltd | Real estate | 2022 |
| Resident Management, Assurance & Security Ltd | Professional & scientific | 2025 |
| Resolve Finances Limited | Other services | 2023 |
| Resourceful Organics Limited | Water & waste | 2013 |
| Resped Solutions Ltd | Health & social care | 2024 |
| Respiratory Analytics Ltd | Information & communication | 2019 |
| Restaurant 37 Ltd | Hospitality | 2023 |
| Retail Systems Technology Limited | Information & communication | 1977 |
| Reup Medical Ltd | Manufacturing | 2025 |
| Revival Blue Foyle Limited | Construction | 2023 |
| Revive by HAN Limited | Administrative & support | 2025 |
| Revive Health Group Limited | Health & social care | 2024 |
| Revsprint Ltd | Information & communication | 2025 |
| REY Mill Ltd | Financial services | 2014 |
| RFE Contracts Limited | Construction | 2025 |
| RGC Contracts Ltd | Construction | 2021 |
| RH Trading Ltd | Wholesale & retail | 2025 |
| Rhanell Fitness Ltd | Arts & recreation | 2026 |
| Richard Sheerin Utilities Limited | Construction | 2025 |
| Richard Smyth Limited | Manufacturing | 2015 |
| Rigging & Lifting Ltd | Manufacturing | 2026 |
| Ritchie Farms Ltd | Agriculture & fishing | 2013 |
| Rivalto Limited | Extraterritorial | 2024 |
| River Media Broadcast Group Limited | Information & communication | 2020 |
| River Radio Bangor Limited | Information & communication | 2024 |
| Riverfront Developments Ltd | Construction | 1999 |
| Rivers Edge Consulting Limited | Professional & scientific | 2017 |
| Riverside Building & Development Limited | Construction | 2001 |
| Riverview Car Sales Ltd | Wholesale & retail | 2018 |
| Riverview Resort Ltd | Hospitality | 2021 |
| Riviera Beauty Limited | Wholesale & retail | 2014 |
| RJB Joinery (Ireland) Limited | Manufacturing | 2018 |
| Rjmt Limited | Real estate | 2015 |
| RK GAS Installations Ltd | Construction | 2002 |
| RKB Business Enterprises Limited | Other services | 2025 |
| RLB Property Management Ltd | Construction | 2015 |
| Rlsac Services Ltd | Professional & scientific | 2018 |
| RM Cloud Solutions Limited | Professional & scientific | 2019 |
| RMB Brickwork Ltd | Construction | 2024 |
| RMC Decorators Ltd | Construction | 2021 |
| RMC Electrical Services Ireland Limited | Construction | 2024 |
| Rmcc Construction Ltd | Construction | 2025 |
| RMH Lettings Ltd | Real estate | 2017 |
| RMM Installations Ltd | Construction | 2020 |
| RNB Enterprises Limited | Professional & scientific | 2015 |
| RNB Projects Limited | Construction | 2005 |
| Roadsafeni Ltd | Information & communication | 2007 |
| Robert Dickson Ltd | Wholesale & retail | 2023 |
| Robert Ferris Estate Agents Limited | Real estate | 2001 |
| Robinson Concrete Ltd | Mining & quarrying | 2013 |