| Seyapay Ltd | Wholesale & retail | 2025 |
| Seymour Management Solutions Ltd. | Real estate | 2020 |
| SF Southampton Limited | Hospitality | 2026 |
| Sfpr Holdings Limited | Professional & scientific | 2010 |
| SG Builders Southern Limited | Construction | 2013 |
| SG Electrical Solutions Ltd | Construction | 2010 |
| SG Garments Ltd | Wholesale & retail | 2024 |
| SG Southern Limited | Construction | 2015 |
| SGM Decor Ltd | Construction | 2019 |
| SGM Painting and Decorating Ltd | Construction | 2026 |
| SGM Support Services Limited | Construction | 2026 |
| SGS Essentials Ltd | Construction | 2026 |
| SGU Solutions Limited | Construction | 2011 |
| SGW Air Conditioning & Refrigeration Services Ltd | Manufacturing | 2025 |
| SGW Systems Ltd | Information & communication | 2015 |
| SH Clinic Ltd | Wholesale & retail | 2022 |
| SH Property Group Ltd | Real estate | 2025 |
| Shabana Ltd | Transport & logistics | 2019 |
| Shades (South) Limited | Other services | 2025 |
| Shadex.Official Ltd | Wholesale & retail | 2025 |
| Shadwell 101 Limited | Real estate | 2020 |
| Shadwell Court (Portsmouth) RTM Company Limited | Households | 2018 |
| Shahsub Limited | Hospitality | 2019 |
| Shake the Nations Ltd | Other services | 2017 |
| Shaping the Future of Portsmouth CIC | Administrative & support | 2016 |
| Sharif SUB Limited | Wholesale & retail | 2026 |
| Sharis (Hampshire) Limited | Administrative & support | 2015 |
| Sharkfire Ltd | Construction | 2018 |
| Sharp Edge Projects Limited | Professional & scientific | 2012 |
| Sharpe Solutions Ltd | Other services | 2023 |
| Sharper Management Limited | Professional & scientific | 2020 |
| Sharpes Investment Group Ltd | Real estate | 2023 |
| Sharpey’S Glass and Glazing Ltd | Construction | 2023 |
| Shattered Silicon Limited | Information & communication | 2000 |
| Shaun Bargains Limited | Wholesale & retail | 2017 |
| Shaun Reynolds Consulting Limited | Professional & scientific | 2013 |
| Shaw Thing Entertainment Ltd | Arts & recreation | 2024 |
| Shawford Projects Ltd | Construction | 2017 |
| Shawyer Construction Limited | Construction | 2011 |
| Shebereal Limited | Wholesale & retail | 2022 |
| Shed of the Dead Productions Ltd | Information & communication | 2014 |
| Shedfield Plumbers Limited | Construction | 2015 |
| Sheerspire Contracts Limited | Real estate | 1998 |
| Sheikh Hub Ltd | Wholesale & retail | 2026 |
| Sheild Services Limited | Real estate | 2003 |
| Shekinah-J Ltd | Other services | 2025 |
| Sheldrake Training Limited | Education | 2016 |
| Shelf Intel Ltd | Professional & scientific | 2025 |
| Shelf Share Ltd | Wholesale & retail | 2020 |
| Shenzhen Ever Link Ltd | Professional & scientific | 2025 |
| Shephard's Contractors Ltd | Energy | 2021 |
| Shepherdshark Property Ltd | Real estate | 2026 |
| Sheppard & Co Portsmouth Limited | Other services | 2020 |
| Sheraton Gate Management Co. Ltd. | Hospitality | 1990 |
| Sherborne Court (Anerley) Limited | Households | 2012 |
| Sherlock Software Limited | Information & communication | 2019 |
| Sherratt & Sherratt Limited | Health & social care | 2022 |
| Shiny Chandeliers Ltd | Wholesale & retail | 2020 |
| Ship Leopard Hotel Limited | Hospitality | 2013 |
| Shobuz Limited | Real estate | 2011 |
| Shona Enterprise Limited | Hospitality | 2018 |
| Shore Nest Clean Limited | Administrative & support | 2025 |
| Shore-Line UXO Mitigation Limited | Professional & scientific | 2021 |
| Shorehaven Construction & Developments Ltd | Construction | 2018 |
| Shoreline Building Services Limited | Construction | 2023 |
| Shoreline Dermatology Ltd | Health & social care | 2024 |
| Showtime Amusements Ltd | Arts & recreation | 2026 |
| SHP Electrical Contracting Ltd | Construction | 2021 |
| Shreevishwa Limited | Information & communication | 2015 |
| Shukhu Limited | Wholesale & retail | 2024 |
| Shuna Bari Limited | Information & communication | 2021 |
| Shundaguoji Limited | Information & communication | 2014 |
| Shuttle Carpentry & Joinery Ltd. | Construction | 2015 |
| SI Digital Ltd | Extraterritorial | 2014 |
| Sian Homes Limited | Wholesale & retail | 2025 |
| Siddiqa's Kitchen Limited | Hospitality | 2024 |
| Sie-Sof Limited | Administrative & support | 2014 |
| Signage Management Solutions Ltd | Administrative & support | 2024 |
| Signage Solutions (Peterborough) Ltd | Administrative & support | 2025 |
| Signature Property Projects Ltd | Real estate | 2026 |
| Sigsacatering Limited | Hospitality | 2024 |
| Silakka Limited | Wholesale & retail | 2024 |
| Silas Holdings Limited | Real estate | 2020 |
| Silent Disco Events Limited | Arts & recreation | 2024 |
| Silent Octopus Holdings Limited | Financial services | 2021 |
| Silhill Investments Limited | Construction | 1960 |
| Silk - Korean Skincare Ltd | Wholesale & retail | 2024 |
| Silk Accounting Solutions Ltd | Professional & scientific | 2018 |
| Sillage Strategies Limited | Professional & scientific | 2026 |
| Siltec Limited | Wholesale & retail | 2019 |
| Silver Airstream Limited | Hospitality | 2020 |
| Silver Palm Foods Ltd | Wholesale & retail | 2022 |
| Silver Piper Limited | Professional & scientific | 2017 |
| Silver Sail Accounting Limited | Professional & scientific | 2021 |
| Silvercoast Paraplanning Services Limited | Professional & scientific | 2019 |
| Silverdale UK Developments Limited | Real estate | 2023 |
| Silverside Holdings Limited | Professional & scientific | 2025 |
| Silverwaters Property Solutions Ltd | Real estate | 2020 |
| Silvester & Sons Plumbing & Heating Services Ltd | Construction | 2019 |
| Simanda Homes Limited | Real estate | 2022 |