| Rickysrails Ltd | Construction | 2016 |
| Ride to Recovery CIC | Wholesale & retail | 2026 |
| Riobree Groundworks Ltd | Construction | 2023 |
| Riverside Barbers Limited | Other services | 2023 |
| RJD Restoration Ltd | Construction | 2022 |
| RKH Catering Ltd | Hospitality | 2026 |
| RMC Homes Limited | Real estate | 2020 |
| Robs Water Services Ltd | Construction | 2024 |
| Romans Roofing Ltd | Construction | 2026 |
| Rosie Stays Ltd | Hospitality | 2025 |
| RS Cuisine Limited | Hospitality | 2023 |
| RS Drywall Systems Limited | Construction | 2024 |
| RTD Electrical Ltd | Construction | 2014 |
| Ruby Red Consulting Ltd | Construction | 2026 |
| Ruby Red Property Ltd | Real estate | 2024 |
| Russell & Son's Builders Ltd | Construction | 2018 |
| RWD Rail Ltd | Construction | 2019 |
| S & D Ceilings Interiors Ltd | Construction | 2018 |
| S Keen Care Ltd | Health & social care | 2023 |
| S&B Drylining Ltd | Construction | 2021 |
| S. & F. Motors Limited | Wholesale & retail | 1967 |
| S.E Builders (South Wales) Limited | Construction | 2014 |
| SAI Sports Limited | Wholesale & retail | 2020 |
| Saints Civils Ltd | Construction | 2025 |
| Sam’S Landscaping Ltd | Wholesale & retail | 2017 |
| Sarpanch Foods Ltd | Hospitality | 2025 |
| SC Decoration Ltd | Construction | 2024 |
| Scissor Twister Ltd | Other services | 2023 |
| Sculptures the Art of Hair Ltd | Other services | 2018 |
| Sealy & Alcock Exteriors Ltd | Construction | 2022 |
| Securikey Locksmiths Ltd | Other services | 2022 |
| Seren Cymru - the Star of Wales Ltd | Hospitality | 2025 |
| Seren Exploration Limited | Professional & scientific | 2009 |
| Service Sync Limited | Information & communication | 2025 |
| Seven Electrical Contractors Limited | Construction | 2025 |
| SF Flooring Solutions Limited | Construction | 2026 |
| Shefford Construction Ltd | Manufacturing | 2025 |
| Shepysbikes Ltd | Wholesale & retail | 2026 |
| Shine F M Consultancy Limited | Administrative & support | 2023 |
| Shree Madhus Ltd | Wholesale & retail | 2018 |
| Shwmae Fried Chicken Ltd | Hospitality | 2024 |
| Shwmae Ltd | Hospitality | 2026 |
| Simon Payne Photography Limited | Professional & scientific | 2014 |
| Sinvula Solutions Ltd | Construction | 2020 |
| SJONES1000000 Ltd | Transport & logistics | 2025 |
| SLF Consultations Ltd | Health & social care | 2024 |
| Smakyb Limited | Hospitality | 2018 |
| Smile Interiors Ltd | Construction | 2021 |
| Sockets N Switches Limited | Construction | 2013 |
| South Wales Kitchen Solutions Ltd | Construction | 2026 |
| South Wales Mortgages Ltd | Financial services | 2022 |
| South Wales Phoenix Groundworks Ltd | Administrative & support | 2020 |
| South Whales Swim School Ltd | Education | 2021 |
| Sparrow Technology Ltd | Wholesale & retail | 2024 |
| Spectacle Theatre Limited | Arts & recreation | 1981 |
| Speedwall Drylining & Plastering Ltd | Construction | 2013 |
| Springclean Cleaning & Laundry Ltd | Other services | 2026 |
| Sps-Building Contractors Limited | Administrative & support | 2017 |
| SR Office Services Ltd | Administrative & support | 2025 |
| SRS Residential Limited | Real estate | 2023 |
| Stacey Hansen Properties Ltd | Real estate | 2021 |
| Star Theatre Company Media Limited | Information & communication | 2019 |
| Station Hotel (Ynyshir) Ltd | Hospitality | 2013 |
| Stephen a Howell Limited | Professional & scientific | 2012 |
| Stephentruelove.Com Limited | Health & social care | 2024 |
| Steve Baker Developments Limited | Households | 2021 |
| Steve Baker Plumbing & Heating Ltd | Construction | 2019 |
| Steve Peachey Ltd | Financial services | 2026 |
| Stratton Sourcing Ltd | Real estate | 2026 |
| Sugar Rush Sweets and Treats Limited | Wholesale & retail | 2025 |
| Summerrae Campers Ltd | Administrative & support | 2023 |
| Summit Renovations Group Limited | Construction | 2026 |
| Swan Therapies Ltd | Health & social care | 2023 |
| T & H Interiors Limited | Construction | 2011 |
| T&T Pressure Washing Services Limited | Administrative & support | 2024 |
| T&Trans Property Ltd | Real estate | 2023 |
| Tallypont Solar Ltd | Energy | 2020 |
| Talyfedw Development Company Limited | Construction | 2022 |
| Tanablas Ltd | Hospitality | 2026 |
| Taste of India (Porth) Ltd | Hospitality | 2024 |
| TB Biomedical Ltd | Professional & scientific | 2023 |
| TBR Property Holdings Limited | Hospitality | 2025 |
| Telecentre and Business School Ltd | Education | 1995 |
| THE Backroom Tonyrefail Ltd | Hospitality | 2024 |
| THE Colliers Arms (Porth) Ltd | Hospitality | 2020 |
| THE Country Grill Limited | Hospitality | 2019 |
| THE Deli Porth Limited | Hospitality | 2018 |
| THE Dirt Warriors Ltd | Administrative & support | 2024 |
| THE Lion Kingdom Ltd | Agriculture & fishing | 2019 |
| THE Pets Empawrium Ltd | Wholesale & retail | 2024 |
| THE POP Factory Ltd | Arts & recreation | 2026 |
| THE Redgate Hotel Ltd | Hospitality | 2013 |
| Thomas of Rhondda Limited | Transport & logistics | 2010 |
| Thomas Viggers Property Services Ltd | Real estate | 2025 |
| Thornes Kitchen Installations Ltd | Construction | 2026 |
| TIM Overson Creative Ltd | Information & communication | 2023 |
| Titan Property Ventures Limited | Real estate | 2024 |
| TJ11 Fitness Ltd | Arts & recreation | 2020 |
| TOI Porth Ltd | Hospitality | 2026 |
| Tombeth Sparkle Cleaning Ltd | Administrative & support | 2026 |