| Stonecrown Limited | Transport & logistics | 2007 |
| Stonehouse CDM Ltd | Professional & scientific | 2020 |
| Stonehouse Commercial Estates Limited | Real estate | 2020 |
| Stonehouse Manufacturing and Retail Limited | Construction | 2020 |
| Stonehouse Mechanic (B&W) Ltd | Wholesale & retail | 2024 |
| Stonehouse Motors SW Ltd | Wholesale & retail | 2024 |
| Stonehouse PWT Centre Ltd | Wholesale & retail | 2018 |
| Stonehouse Repairs Ltd | Wholesale & retail | 2024 |
| Stonehouse Windows Limited | Construction | 2017 |
| Stonemade Ltd | Manufacturing | 2018 |
| Stoneyford Ventures Ltd | Real estate | 2025 |
| Stopby Car Wash Ltd | Administrative & support | 2019 |
| Storage and Marine Services Ltd. | Manufacturing | 2016 |
| Storage Plymouth Limited | Transport & logistics | 2017 |
| Storm Plymouth CIC | Arts & recreation | 2019 |
| Stormforce Holdings Ltd | Financial services | 2023 |
| Stormforce Roofing and Maintenance Limited | Construction | 2003 |
| Stormseal (South West) Limited | Construction | 2001 |
| Stormy Studio Ltd | Information & communication | 2013 |
| Story Juice Limited | Information & communication | 2012 |
| Stowford Business Park Management Co Ltd | Households | 2018 |
| Stowford Furniture Ltd | Extraterritorial | 2018 |
| Stoyan Taylor Limited | Professional & scientific | 2014 |
| STP Building and Maintenance Ltd | Construction | 2023 |
| STR & Co SW Ltd | Hospitality | 2019 |
| STR Security Solutions Ltd | Administrative & support | 2020 |
| Strange Lettings Ltd | Real estate | 2018 |
| Strategic Catalyst Consulting Limited | Professional & scientific | 2026 |
| Strategic Prosperity Ltd | Financial services | 2016 |
| Stratenture Advisory Ltd | Information & communication | 2025 |
| Stratioti Ltd | Professional & scientific | 2024 |
| Stray Park (Management) Co. Limited | Households | 1965 |
| Streetside Shine Ltd | Wholesale & retail | 2025 |
| Stretton's Creek Limited | Manufacturing | 2025 |
| Stride & Sole Podiatry Ltd | Health & social care | 2026 |
| Stringers Catering Ltd | Hospitality | 2025 |
| Strive Engineering Services Ltd | Construction | 2025 |
| Strive Supps Ltd | Wholesale & retail | 2025 |
| Stronger ME CIC | Education | 2022 |
| Stronta Investigations Limited | Administrative & support | 2022 |
| Structural Evolution Ltd | Professional & scientific | 2020 |
| Stuart ASH Mortgage Services Limited | Financial services | 2024 |
| Stuart Elford Associates Ltd | Professional & scientific | 2025 |
| Stuart Jolley Electrical Ltd | Construction | 2021 |
| Stuart Road Amenity Limited | Households | 2005 |
| Stuart Road Ltd | Transport & logistics | 2018 |
| Stuart Road Management Limited | Households | 1989 |
| Stuart Road Properties Limited | Households | 1982 |
| Student Choice Plymouth Ltd | Hospitality | 2013 |
| Student Life Plymouth Limited | Real estate | 2017 |
| Student Property Portals Limited | Information & communication | 2018 |
| Student Radar Ltd | Information & communication | 2026 |
| Student Rooms 4 Plymouth Ltd | Real estate | 2012 |
| Student Units Limited | Real estate | 2005 |
| Students and Refugees Together (Start) | Health & social care | 2004 |
| Studio 44 (Plymouth) Ltd | Other services | 2017 |
| Studio Gorse Ltd | Professional & scientific | 2022 |
| Studio HD Ltd | Manufacturing | 2024 |
| Studio One South West Ltd | Construction | 2011 |
| Studio PL1 Ltd | Manufacturing | 2024 |
| Studio Simon Edwin Ltd | Information & communication | 2014 |
| Studio Skein EOT Ltd | Other services | 2020 |
| Studio Skein Ltd | Professional & scientific | 2004 |
| Studiojb Architectural Services Limited | Professional & scientific | 2005 |
| Sturdy Homes Limited | Real estate | 2022 |
| Sturdy Transport Limited | Transport & logistics | 2023 |
| Stvproperty Limited | Information & communication | 2014 |
| Style Centre Plymouth Ltd | Other services | 2018 |
| Style Wind Down Limited | Professional & scientific | 2011 |
| SUB Dimension Ltd | Professional & scientific | 2017 |
| Subotix Ltd | Professional & scientific | 2013 |
| Subzero DRY Ice Blasting (SW) Ltd | Administrative & support | 2025 |
| Successful CRM Ltd | Professional & scientific | 2014 |
| Succession Advisory Services Limited | Financial services | 2008 |
| Succession Employee Benefit Solutions Limited | Financial services | 2012 |
| Succession Financial Management Limited | Financial services | 2002 |
| Succession Group Ltd | Financial services | 2011 |
| Succession Holdings Ltd | Financial services | 2012 |
| Succession Wealth Management Limited | Financial services | 2011 |
| Succulent Events Ltd | Hospitality | 2026 |
| Sudanese Community for Women and Children in Plymouth CIC | Education | 2024 |
| SUE Plymouth Limited | Hospitality | 2020 |
| Sugar Quay Holdings Limited | Financial services | 2018 |
| Sugar Quay Limited | Construction | 2018 |
| Sugarplum Soft Play Limited | Administrative & support | 2025 |
| Sukkunda Limited | Extraterritorial | 2019 |
| Sulmara GEO Limited | Administrative & support | 2020 |
| SUMMER81 Ltd | Health & social care | 2022 |
| Summit 2 Seabed Ltd | Professional & scientific | 2020 |
| Summit Padel Ltd | Arts & recreation | 2025 |
| Sun Machine Studio Limited | Professional & scientific | 2025 |
| Sun Water Coolers Ltd. | Manufacturing | 2000 |
| Sundico Group Ltd | Administrative & support | 2023 |
| Sunny Banks Estates Limited | Construction | 1968 |
| Sunnybanks Homes (SW) Management Limited | Administrative & support | 2004 |
| Sunnymeade Quality Care Ltd. | Health & social care | 2011 |
| Sunray FLY Fish Limited | Wholesale & retail | 2014 |
| Sunrise Cottages Limited | Real estate | 2018 |
| Sunset Lodge Housing Services Ltd | Real estate | 2016 |
| Sunset Sounds Limited | Arts & recreation | 2025 |