| Rhino Electrical Services Limited | Construction | 2016 |
| Rhodri Morris Costs Ltd | Other services | 2014 |
| Rhondda Scaffolding Limited | Construction | 2017 |
| Richard Phelps Ltd | Financial services | 2012 |
| Rickythebricky Ltd | Construction | 2025 |
| Riscapital Limited | Arts & recreation | 2004 |
| Riskmonitor Holdings Limited | Financial services | 2012 |
| Riskmonitor Limited | Information & communication | 2005 |
| Riverbank Pontyclun Limited | Hospitality | 2019 |
| RJC FLY Rods Ltd | Manufacturing | 2020 |
| Rjcmedia Ltd | Information & communication | 2025 |
| RJD Property Group Ltd | Construction | 2022 |
| RJM Electro-Mechanical Services Limited | Manufacturing | 2008 |
| RM & Sons Rendering Ltd | Construction | 2016 |
| RM Assets Limited | Wholesale & retail | 2014 |
| RM Experience Limited | Arts & recreation | 2017 |
| RM Wynt Limited | Energy | 2017 |
| RMX Technology Solutions Ltd | Information & communication | 2019 |
| Roadways Tyre & Auto Services Ltd | Wholesale & retail | 2009 |
| Robert Hobbs Taxation Services Ltd | Professional & scientific | 2014 |
| Roberts Accountancy & Bookkeeping Ltd | Professional & scientific | 2023 |
| Roberts Property Consultants Limited | Real estate | 2018 |
| Robinson Medical and Property Holdings Ltd | Households | 2026 |
| Roccos Investments Ltd | Real estate | 2023 |
| Rock IT Leisure Limited | Hospitality | 2024 |
| Rocket Four Media Ltd | Other services | 2023 |
| Rooftop Tiling (Wales) Limited | Construction | 1997 |
| Rookswood Ltd | Construction | 2013 |
| Ross David Carpentry Limited | Manufacturing | 2023 |
| Rossi Heating & Plumbing Ltd | Construction | 2023 |
| Rossi Properties Wales Ltd | Real estate | 2025 |
| Rossllew Ltd | Transport & logistics | 2025 |
| Roughfield Limited | Agriculture & fishing | 2025 |
| Royal Mint Services Limited | Administrative & support | 1945 |
| RSP Plumbing and Heating Ltd | Construction | 2014 |
| Rusty Design Limited | Professional & scientific | 2017 |
| RW Thomas Fencing and Groundworks Limited | Construction | 2014 |
| Rwke Holdings Limited | Real estate | 2021 |
| Ryan Stephens Plant Hire Ltd | Administrative & support | 2017 |
| Rybec Homes Limited | Real estate | 2013 |
| Rybyn Property Limited | Households | 2025 |
| Ryco Limited | Real estate | 1972 |
| Rycon Tool Hire and Sales Ltd | Wholesale & retail | 2000 |
| Rycon Toolhire Ltd | Extraterritorial | 2001 |
| Rymont Estates Ltd | Real estate | 2022 |
| S & JA Management Ltd | Real estate | 2023 |
| S G Tyres Ltd | Wholesale & retail | 2020 |
| S&C DM Ltd | Administrative & support | 2019 |
| S. a. W. Accounting Ltd | Professional & scientific | 2022 |
| S.J.S. Services (Wales) Limited | Construction | 2007 |
| Safeux Solutions Ltd | Professional & scientific | 2025 |
| Saint Sannans Management Co Limited | Households | 2025 |
| Sall and Sall Ltd | Real estate | 2018 |
| Sall Investments Limited | Real estate | 2002 |
| Sands Private Health Clinic Limited | Health & social care | 2016 |
| Savvy Wealth Management Ltd | Financial services | 2011 |
| Sbqs Ltd | Professional & scientific | 2026 |
| Scaie AV8 Ltd | Manufacturing | 2023 |
| Scan and Collate Limited | Administrative & support | 2007 |
| SCB Group Limited | Construction | 2023 |
| Scott Thomas Brickwork Ltd | Construction | 2026 |
| Scourge Scenics Ltd | Manufacturing | 2020 |
| Scrum Property Ltd | Real estate | 2007 |
| Seculuxe Limited | Manufacturing | 2020 |
| Seecue Ltd | Professional & scientific | 2022 |
| Selca Ltd | Education | 2009 |
| Senfast Ltd | Information & communication | 2012 |
| Seren Manufacturing Ltd | Manufacturing | 2018 |
| Seriously Driven Ltd | Wholesale & retail | 2017 |
| Seth Hill & SON Limited | Mining & quarrying | 1952 |
| Sharon Dixon Coaching Limited | Professional & scientific | 2011 |
| Shawre Barbers Ltd | Other services | 2025 |
| Shere Punjab Entertainment Ltd. | Arts & recreation | 2017 |
| Shield HD Ltd | Administrative & support | 2019 |
| Shoot From the HIP Films Ltd | Arts & recreation | 2014 |
| Shoots & Roots Landscaping Ltd | Construction | 2019 |
| Sigma 3 (Holdings) Limited | Financial services | 2000 |
| Sigma 3 (Kitchens) Limited | Manufacturing | 1977 |
| Sigma 3 Group Ltd | Financial services | 2021 |
| Signature Commercial Consultancy Limited | Professional & scientific | 2026 |
| Sigra Holdings Ltd | Financial services | 2023 |
| Silkroad Gardens Limited | Wholesale & retail | 2024 |
| Silverback Books Ltd | Manufacturing | 2013 |
| Silverback Security Ltd | Administrative & support | 2021 |
| Silverbadge Limited | Hospitality | 2003 |
| Silverlink Support Services Limited | Real estate | 2023 |
| SIM Life Giveaways Ltd | Arts & recreation | 2024 |
| Simofic Limited | Wholesale & retail | 2024 |
| Sined Limited | Wholesale & retail | 2019 |
| Sion Bebb Golf Limited | Arts & recreation | 2013 |
| SJ Flower the Building Company Ltd | Construction | 2011 |
| SK & a Solutions Ltd | Real estate | 2023 |
| Skill-Fix Interiors Ltd | Construction | 2007 |
| Slade Logistics Ltd | Transport & logistics | 2022 |
| SM Catering Services Ltd | Hospitality | 2025 |
| Smart Gedi Ltd | Professional & scientific | 2021 |
| Smartbuymotors Ltd | Wholesale & retail | 2020 |
| SMC Kitchens Limited | Construction | 2013 |
| Smughouse Ltd | Manufacturing | 2019 |
| Solutions Occupational Health and Wellbeing Ltd | Health & social care | 2025 |