| Semigood Limited | Construction | 1988 |
| SGH Project Management Limited | Professional & scientific | 2026 |
| Shashow Ltd | Other services | 2023 |
| Sheenashona Corporate Limited | Financial services | 2014 |
| Sheenashona Limited | Manufacturing | 2011 |
| Sheff Energy Ltd | Professional & scientific | 2024 |
| Sheila Kerr Jewellery Limited | Arts & recreation | 2014 |
| SHM Travel Ltd | Transport & logistics | 2016 |
| Shza Ltd | Other services | 2025 |
| Silverburn Investments Limited | Financial services | 2009 |
| Simply Brokering Ltd | Financial services | 2020 |
| Sims IT Services Ltd | Administrative & support | 2015 |
| SJA Scotland Limited | Extraterritorial | 2023 |
| SJM Music Limited | Arts & recreation | 2026 |
| Skinz Beauty Clinic Ltd | Other services | 2022 |
| SKL Services Limited | Administrative & support | 2000 |
| SLA97 Ltd | Other services | 2023 |
| Sledmere Travel Services Ltd. | Professional & scientific | 2017 |
| Slinky Thinkers Limited | Education | 2025 |
| SM Storey Ltd. | Administrative & support | 2004 |
| Smart Choice Pensions Ltd | Financial services | 2016 |
| Smttoday Limited | Administrative & support | 2013 |
| SNP Engineering Limited | Administrative & support | 2011 |
| Sofisticuts Limited | Other services | 2010 |
| Solar Leisure Prestwick Ltd. | Other services | 2009 |
| SOO & Co Holdings Ltd | Financial services | 2026 |
| Speedy Ironing Services Limited | Administrative & support | 2004 |
| Spence Property Trading Ltd | Real estate | 2024 |
| Spraytech Ayrshire Limited | Administrative & support | 2014 |
| Stanecastle Homes Limited | Construction | 2013 |
| Starry Sky Prestwick Ltd | Hospitality | 2025 |
| Steel Giraffe Limited | Administrative & support | 2011 |
| Steel Property Management Ltd | Real estate | 2020 |
| Steven Cowan Plumbing & Heating Ltd | Households | 2021 |
| Storr Access Ltd | Professional & scientific | 2018 |
| Stramach Ltd | Administrative & support | 2011 |
| Streamline Taxis Largs Limited | Transport & logistics | 2015 |
| Studio Code Ltd | Information & communication | 2019 |
| Sub-C-Ark Limited | Administrative & support | 2004 |
| Subsea Financial Services Limited | Administrative & support | 2008 |
| Subsea IQ Ltd | Administrative & support | 2011 |
| Swoon Boutique Ltd | Wholesale & retail | 2022 |
| Tagger Moon Limited | Professional & scientific | 2010 |
| Tara Consultancy Ltd | Professional & scientific | 2018 |
| Tara Properties (Scotland) Limited | Real estate | 2022 |
| TCK Trading Ltd | Hospitality | 2026 |
| TDP Roofing Services Ltd | Construction | 2023 |
| Tebfg Ltd | Professional & scientific | 2025 |
| Technik 9 Ltd | Wholesale & retail | 2022 |
| Technorigging North Ltd | Professional & scientific | 2026 |
| Teeny Tails Ltd | Other services | 2023 |
| Templar Serv Limited | Administrative & support | 2012 |
| THE Ayrshire Chamber of Commerce and Industry | Other services | 1989 |
| THE Burger Bar Ltd | Hospitality | 2023 |
| THE Caberdawn Partnership | | 1995 |
| THE Eckford Partnership Ltd | Arts & recreation | 2013 |
| THE Food Trough Limited | Hospitality | 2022 |
| THE Hair and Beauty Club Limited | Other services | 2024 |
| THE Mobile Scullery Ltd | Hospitality | 2020 |
| THE Pawsitive Cabin Limited | Extraterritorial | 2025 |
| THE Pinpoint Plan Limited | Administrative & support | 2005 |
| THE Post Box Prestwick Ltd | Transport & logistics | 2013 |
| THE Ropery (Hebburn) Management Company Limited | Households | 2024 |
| THE Sandstone Renovation Company Limited | Construction | 2025 |
| THE Scottish Association of Local Sports Councils | Arts & recreation | 2010 |
| THE Star Minimarket Ltd | Wholesale & retail | 2026 |
| THE Tattie Shack Ltd | Wholesale & retail | 2022 |
| THE Tile Boutique (Ayrshire) Ltd | Wholesale & retail | 2025 |
| THE View @ Monktonhill Ltd | Hospitality | 2024 |
| THE WEE House Company Ltd | Construction | 2021 |
| THE Yellow Brick Road Group Ltd | Education | 2017 |
| THE Young Programme Limited | Education | 2005 |
| THE2MS Limited | Hospitality | 2017 |
| Thermatech (Scotland) Ltd | Construction | 2025 |
| They Bake Ltd | Manufacturing | 2020 |
| Think Aesthetics Ltd | Professional & scientific | 2017 |
| Thorpe Project Management Limited | Administrative & support | 2001 |
| Tina King Travel Limited | Administrative & support | 2007 |
| TLC (Scotland) Limited | Health & social care | 2019 |
| TLC Decorating Ltd | Construction | 2023 |
| TLC Training Academy Limited | Health & social care | 2025 |
| TOM Mcghee Trading Ltd | Professional & scientific | 2023 |
| Total Weed Solutions Limited | Administrative & support | 2013 |
| Tourbas Limited | Wholesale & retail | 2020 |
| TRANSK9 Limited | Wholesale & retail | 2017 |
| TRASH2CASH Ltd. | Other services | 2008 |
| Travelwhiz Ltd | Information & communication | 2013 |
| Troon Property Factoring Services Limited | Administrative & support | 2015 |
| Troon TUG Company Limited | Transport & logistics | 2008 |
| TS Aero Maintenance Services Ltd | Manufacturing | 2026 |
| Tswg Holdings Limited | Financial services | 2025 |
| TTS Environmental Limited | Professional & scientific | 1991 |
| TW Recruitment Solutions Limited | Administrative & support | 2017 |
| Twvp Ltd | Administrative & support | 2024 |
| Tyme Limited | Construction | 1983 |
| UBK Engineering Group Ltd | Manufacturing | 2022 |
| Underwater Works Limited | Administrative & support | 2005 |
| Unibarber Limited | Other services | 2002 |
| UP4LEARNING (UK) Ltd | Education | 2014 |
| Uppal Properties Glasgow Limited | Real estate | 2024 |