| ST Minver Developments Limited | Construction | 2017 |
| ST Minver House Care Home Limited | Health & social care | 2022 |
| ST Minver Property (South West) Limited | Construction | 2017 |
| ST Minver Property Investments Limited | Construction | 2013 |
| ST Piran Holdings Limited | Administrative & support | 2005 |
| ST Piran Homes Limited | Construction | 1993 |
| ST Saviours Community Interest Company | Education | 2015 |
| ST Thomas Court Amenity Areas Management Company Limited | Households | 2007 |
| ST Thomas Court Management Company (Penryn) Limited | Households | 2007 |
| ST Vincent Court Amenity Limited | Real estate | 2010 |
| ST. Budeaux Retailers Limited | Wholesale & retail | 2024 |
| ST. Michael's Terrace Gardens Management Company Limited | Households | 2010 |
| ST. Nikitas & ST. Demetrios Greek Orthodox Church of Plymouth Limited | Other services | 1996 |
| ST. Peter's Court Management (Plymouth) Limited | Households | 1985 |
| ST. Thomas Court Apartments Ltd | Households | 2019 |
| Stack'D & Loaded Limited | Hospitality | 2026 |
| Stackhouse Design Ltd | Professional & scientific | 2020 |
| Staddiscombe Garage Limited | Wholesale & retail | 2005 |
| Staddiscombe Park Limited | Hospitality | 1997 |
| Staddon Heights Management Company Limited | Households | 2021 |
| Staddon Management Company Limited | Real estate | 1999 |
| Stads Roofing and Solar Ltd | Construction | 2026 |
| Stainless Fabs Limited | Manufacturing | 2010 |
| Stairport Trans Ltd | Wholesale & retail | 2016 |
| Stakworks Limited | Information & communication | 2012 |
| Stalmaster Ltd | Manufacturing | 2021 |
| Stamer Developments Ltd | Real estate | 2014 |
| Stamford Court Management Company Limited | Households | 1980 |
| Stamford Quay Residents Limited | Administrative & support | 1984 |
| Stanley Air Conditioning Ltd | Professional & scientific | 2020 |
| Stanlo Construction Limited | Construction | 2023 |
| Stapleton Holdings Limited | Real estate | 2019 |
| Star Game Studios Limited | Information & communication | 2022 |
| Star Garage Plymouth Ltd | Wholesale & retail | 2025 |
| Star Oven Cleaning Services Ltd | Administrative & support | 2016 |
| Starags Ltd | Hospitality | 2022 |
| Starbooks Limited | Professional & scientific | 2016 |
| Starbuild Developments Limited | Construction | 1991 |
| Starfish Souvenirs & Gifts Ltd | Wholesale & retail | 2013 |
| Stargeneralmerchandise Ltd | Wholesale & retail | 2025 |
| Starr Finishings Limited | Construction | 2001 |
| Stars Gyms Holdings Limited | Financial services | 2024 |
| Stars Gyms Limited | Arts & recreation | 2008 |
| Stars Gyms Site 2 Limited | Arts & recreation | 2024 |
| Starskysun Consulting Ltd | Professional & scientific | 2026 |
| Starskysun Holdings Limited | Financial services | 2025 |
| Start Point INS Solutions Ltd | Professional & scientific | 2026 |
| Start Point Sail West Limited | Transport & logistics | 2001 |
| Start With Smart Limited | Wholesale & retail | 2017 |
| Stasis Media Limited | Administrative & support | 2008 |
| Station View Garage Limited | Wholesale & retail | 2002 |
| Stax Reclamation Limited | Wholesale & retail | 2002 |
| Stay Weird Surf Ltd | Wholesale & retail | 2020 |
| Stay-Dry Roofing (SW) Ltd | Construction | 2018 |
| Staybrite Cleaning Services Ltd | Administrative & support | 2013 |
| STB Marketing & Consultancy Ltd | Administrative & support | 2022 |
| Steamin Mugg Ltd | Manufacturing | 2019 |
| Sted Interiors Ltd | Construction | 2017 |
| Steele Consulting Ltd | Professional & scientific | 2025 |
| Steelform Construction Services Ltd | Construction | 2021 |
| Steer Pipe Fitting Services Ltd | Construction | 2016 |
| Stefan Karina Ltd | Public administration | 2023 |
| Stellar AI Labs UK Limited | Information & communication | 2024 |
| Stellium Ltd | Information & communication | 2013 |
| Stem K Solutions Ltd | Construction | 2023 |
| Step UP Speech & Language Ltd | Education | 2018 |
| Stephanie Nicole Ltd | Other services | 2019 |
| Stephen GUY Consulting Ltd | Financial services | 2026 |
| Stephen Williams Limited | Construction | 2000 |
| Stephens & Couch Ltd | Real estate | 2024 |
| Stephens Dairies (Plympton) Limited | Real estate | 1949 |
| Steps Ahead Care & Support Limited | Health & social care | 2009 |
| Stepview Property Management Limited | Households | 1990 |
| Sterling Global Limited | Wholesale & retail | 2005 |
| Sterling Health and Safety Ltd | Construction | 2025 |
| Steve & Emma Bartlett Limited | Other services | 2014 |
| Steve England Property Limited | Real estate | 2015 |
| Steve Green Haulage Ltd | Transport & logistics | 2025 |
| Steve Hosking Plumbing & Heating Ltd | Construction | 2019 |
| Steve Lamb Pipefitting Limited | Construction | 2003 |
| Steve Leach Limited | Real estate | 2005 |
| Steve Northmore Retail Limited | Wholesale & retail | 1987 |
| Steve Piper Autos Ltd | Wholesale & retail | 2025 |
| Steven Capper Ltd | Public administration | 2014 |
| Steven Kelly Ltd | Professional & scientific | 2023 |
| Steven Lakey Building Design Limited | Professional & scientific | 2016 |
| Stevensonvisuals Photography Ltd | Transport & logistics | 2025 |
| Stewart Rail Ltd | Construction | 2019 |
| Still Window Cleaning Limited | Administrative & support | 2017 |
| Stiltskin Creative Arts & Theatre Company C.I.C. | Education | 2008 |
| Stirling Place Management Limited | Households | 1990 |
| Stitchtrove Ltd | Wholesale & retail | 2022 |
| Stoke Bar Ltd | Hospitality | 2019 |
| Stoke Barber Ltd | Other services | 2023 |
| Stoke Fish & Kebab Ltd | Hospitality | 2026 |
| Stoke Grill and Pizza Ltd | Hospitality | 2023 |
| Stoke Grill (SW) Ltd | Hospitality | 2025 |
| Stoke Grill Ltd | Hospitality | 2018 |
| Stoke Grill Takeaway Ltd | Hospitality | 2025 |
| Stokeley Manor Management Limited | Households | 1987 |