| Roose & Andersons Ltd | Professional & scientific | 2019 |
| Rooted Life Ltd | Education | 2023 |
| Ropeworks Active Limited | Arts & recreation | 2016 |
| Ross & Hughes Carpets Limited | Construction | 2001 |
| Ross Shellfish Bigorneaux Limited | Agriculture & fishing | 2014 |
| Royal Welsh Yacht Club Limited | Arts & recreation | 2024 |
| Royal Yachting Association Cymru.Wales - Cymdeithas Hwylio Brenhinol Cymru.Wales | Arts & recreation | 1994 |
| Rudlin & Co Ltd | Professional & scientific | 2025 |
| RWH Fabrications Ltd | Administrative & support | 2017 |
| Rwst Consultancy Ltd | Professional & scientific | 2012 |
| S M Jones Electrical Ltd | Manufacturing | 2013 |
| S.A.R Deliveries Ltd | Transport & logistics | 2025 |
| Safi (NW) Ltd | Hospitality | 2023 |
| Sain (Recordiau) Cyfyngedig | Information & communication | 1969 |
| Sandblasting & Spraying Limited | Construction | 2023 |
| Santalum Ltd | Professional & scientific | 2019 |
| Sara Lois Jewellery Ltd | Manufacturing | 2023 |
| Saron Enterprises Limited | Information & communication | 2008 |
| Scaffmate Hire Ltd | Administrative & support | 2023 |
| Scrs Investments Ltd | Education | 2014 |
| Seilo CYF | Health & social care | 2024 |
| Seiont Research Limited | Professional & scientific | 2012 |
| Seiril Owens Finance Ltd | Professional & scientific | 2023 |
| Semaphore Software Ltd | Information & communication | 2024 |
| Seren CMT Ltd | Professional & scientific | 2013 |
| Seren Fach Cleaning Services Ltd | Administrative & support | 2025 |
| Serene Lodges Ltd | Real estate | 2021 |
| Sern Management Limited | Households | 2025 |
| Sezco Enterprises Limited | Real estate | 2001 |
| Shilling & Shoker Enterprises. Ltd | Wholesale & retail | 2015 |
| Shiwr Ltd | Manufacturing | 2016 |
| Shoker 11 Limited | Wholesale & retail | 2012 |
| Shoker Limited | Wholesale & retail | 2003 |
| Sierra Collective Ltd | Wholesale & retail | 2025 |
| Sigma Projects Ltd | Construction | 2024 |
| Simulator Logic Ltd | Manufacturing | 2016 |
| Sioned Hughes Limited | Wholesale & retail | 2019 |
| Siop Elidir Ltd | Wholesale & retail | 2016 |
| Siop Morgeisi Direct Mortgages Limited | Financial services | 2001 |
| Skinovation Aesthetics Ltd | Health & social care | 2024 |
| Skyline Tree Services Limited | Agriculture & fishing | 2012 |
| SLA Housing Services Limited | Real estate | 2021 |
| Small Medows Limited | Wholesale & retail | 2022 |
| Smart Storm Ltd | Manufacturing | 2012 |
| Smart Tune Limited | Wholesale & retail | 2007 |
| Smith & Aslin Ltd | Information & communication | 2016 |
| Smithy Mechanical Services Ltd | Professional & scientific | 2022 |
| Smwddis Swig Smoothies CYF | Hospitality | 2023 |
| Snac Hapus Ltd | Hospitality | 2026 |
| Snowdonia Adventures Limited | Arts & recreation | 2004 |
| Snowdonia Drilling and Concrete Cutting Ltd | Professional & scientific | 2025 |
| Snowdonia Fire Protection Holdings Limited | Financial services | 2026 |
| Snowdonia Luxury Glamping - Gwersylla Moethus Eryri CYF | Hospitality | 2020 |
| Snowdonia Refrigeration and Air Conditioning Ltd | Construction | 2013 |
| Snowdonia Riding Stables Ltd | Other services | 2019 |
| Snowdonia Taxis Ltd | Transport & logistics | 2019 |
| Snowdonia Watersports Limited | Arts & recreation | 2016 |
| Solar Renewable Hub Limited | Wholesale & retail | 2023 |
| Sonata Media CYF. | Information & communication | 2023 |
| SOO Cool Ltd | Wholesale & retail | 2003 |
| Specialist Industrial Rope Access Solutions Limited | Construction | 2017 |
| Spherical Harmonics Limited | Information & communication | 2017 |
| Spice Peak Limited | Hospitality | 2026 |
| Spraycrete Limited | Mining & quarrying | 2025 |
| Squeeze Climbing Products Ltd | Manufacturing | 2021 |
| SSK International Trading Ltd | Wholesale & retail | 2025 |
| SSL Cottages Limited | Hospitality | 2023 |
| Stacey Bar CYF | Hospitality | 2026 |
| Steel Scaffolding Ltd | Construction | 2009 |
| Stepping Outdoors Limited | Education | 2012 |
| Steven Jones Gallery Ltd | Arts & recreation | 2003 |
| Stones 4 Hole in the Wall Ltd | Hospitality | 2014 |
| Stove & Flue Services Limited | Manufacturing | 2015 |
| Strong Mind Ltd | Arts & recreation | 2021 |
| Studio Griffiths Ltd | Arts & recreation | 2025 |
| Subvectiio Limited | Transport & logistics | 2024 |
| Summit View Ltd | Real estate | 2024 |
| Summits & Trails Ltd | Administrative & support | 2023 |
| Sustainable Places for Animals, Community and Education Cyfyngedig | Education | 2024 |
| Sustained Support Ltd | Extraterritorial | 2005 |
| Syeds Boutique Ltd | Manufacturing | 2024 |
| Sygun Fawr Limited | Hospitality | 2008 |
| Synergy Rock Ltd | Construction | 2026 |
| SÊT Fawr PAC | | 2019 |
| T J Pritchard Limited | Administrative & support | 2007 |
| Taco Loco Street Food Ltd | Hospitality | 2025 |
| Tacsi HUW Ltd | Transport & logistics | 2024 |
| Tacsi Penrhyn Taxi CYF | Transport & logistics | 2019 |
| Tacsi Robat Cyfyngedig | Transport & logistics | 2013 |
| Tafarn YR Eagles Ltd | Hospitality | 2025 |
| TAI DA Homes CYF. | Real estate | 2025 |
| TAI LON Y Parc CYF | Hospitality | 2019 |
| TAI M&C Ltd | Real estate | 2025 |
| TAI Rhosyn Limited | Real estate | 2018 |
| TAI Ry's Limited | Real estate | 2026 |
| TAI TOM CYF | Real estate | 2022 |
| Take the Dirt Path Ltd | Professional & scientific | 2021 |
| Tanau PLW Fires Limited | Construction | 2024 |
| Tandoori Penygroes Ltd | Hospitality | 2021 |
| Tantalus Holdings Ltd | Professional & scientific | 2017 |