| Sobaaa Ltd | Manufacturing | 2025 |
| Sobar Property Limited | Hospitality | 2019 |
| Sobar Southampton Limited | Hospitality | 2010 |
| Soberton House (Freehold) Limited | Households | 2008 |
| Soberton House RTM Company Limited | Households | 2007 |
| Soberton Software Ltd | Information & communication | 2026 |
| Sobstad Sailmakers (UK) Limited | Manufacturing | 2006 |
| Sobuild Limited | Construction | 2017 |
| Sobuildit Limited | Professional & scientific | 2015 |
| Soca Shack Limited | Hospitality | 2020 |
| SOCAL89 Limited | Wholesale & retail | 1989 |
| Sochi Recruitment Services Ltd | Administrative & support | 2024 |
| Social Agency Ltd | Professional & scientific | 2021 |
| Social Bar (Portswood) Ltd. | Hospitality | 2017 |
| Social Care in Action | Health & social care | 2002 |
| Social Sphere Group Ltd | Professional & scientific | 2026 |
| Socialballher Limited | Arts & recreation | 2024 |
| Society of Consulting Marine Engineers and Ship Surveyors(The) | Other services | 1920 |
| Socionics Britannica Ltd. | Information & communication | 2014 |
| Socleen Limited | Administrative & support | 2025 |
| Soco Music Project | Education | 2009 |
| Soco Organisation Ltd | Administrative & support | 2021 |
| Soeth Properties Ltd | Real estate | 2023 |
| Sofa Supreme Ltd | Wholesale & retail | 2016 |
| Soffra UK Ltd | Wholesale & retail | 2021 |
| Soft Spedition Limited | Transport & logistics | 2019 |
| Softech Engineering Ltd | Information & communication | 2021 |
| Softei.Com Limited | Administrative & support | 2013 |
| Softline Information Technology Limited | Information & communication | 2026 |
| Softset Design Limited | Information & communication | 2014 |
| Softwarence Ltd | Information & communication | 2025 |
| Softwave Group Ltd | Information & communication | 2023 |
| Sogo Systems Limited | Information & communication | 2025 |
| Sohaib Mian Ltd | Wholesale & retail | 2024 |
| Sohail Property Investments Ltd | Real estate | 2021 |
| Sohbar Ltd | Hospitality | 2025 |
| Sohi Constructions Ltd | Construction | 2018 |
| Soho Dean Street Ltd | Hospitality | 2023 |
| Sojack Limited | Professional & scientific | 2019 |
| Sojo Property Investments Limited | Real estate | 2025 |
| Soko Clinic Limited | Other services | 2024 |
| SOL Care/Rgn Ltd | Health & social care | 2025 |
| SOL Explore Travel Ltd | Professional & scientific | 2023 |
| SOL Plumbing & Heating Services Ltd | Construction | 2017 |
| Solace Sauna Ltd | Other services | 2024 |
| Solace Utilities Limited | Information & communication | 2019 |
| Solar Allotments Limited | Extraterritorial | 2020 |
| Solar Clean Dorset Ltd | Administrative & support | 2025 |
| Solar Clean Hampshire Ltd | Administrative & support | 2025 |
| Solar HUT Ltd | Construction | 2022 |
| Solar Life Ltd | Professional & scientific | 2024 |
| Solar Parto Tech Ltd | Energy | 2024 |
| Solar Supplies and Services Limited | Wholesale & retail | 2014 |
| Solaris Blinds Ltd | Wholesale & retail | 2010 |
| Solarlumina Solutions Ltd | Construction | 2024 |
| Solas Marine Ltd | Wholesale & retail | 2015 |
| Soldela Group Ltd | Information & communication | 2025 |
| Soldierhood Ltd | Wholesale & retail | 2026 |
| Soldis Ltd | Wholesale & retail | 2025 |
| Solead Energy Ltd | Manufacturing | 2024 |
| Solefinds Limited | Wholesale & retail | 2026 |
| Solent Accountancy Training Limited | Education | 1986 |
| Solent Acquisitions Limited | Real estate | 2012 |
| Solent Adventure Sailing Limited | Hospitality | 1999 |
| Solent Adventures Limited | Agriculture & fishing | 2025 |
| Solent Afrolinks Limited | Wholesale & retail | 2021 |
| Solent Airport Transfer Ltd | Transport & logistics | 2025 |
| Solent Automotive Solutions Ltd | Professional & scientific | 2023 |
| Solent Bathrooms Limited | Extraterritorial | 2026 |
| Solent Behaviour Consultancy Ltd | Extraterritorial | 2023 |
| Solent Bespoke Projects Limited | Construction | 2025 |
| Solent Blue Services Limited | Professional & scientific | 2015 |
| Solent Boat Care Limited | Manufacturing | 2020 |
| Solent Building Solutions Ltd | Construction | 2020 |
| Solent CAFE2U Ltd | Hospitality | 2014 |
| Solent Capital Group Ltd | Financial services | 2026 |
| Solent Cars Limited | Transport & logistics | 2024 |
| Solent Children's Centre Limited | Education | 1998 |
| Solent Chronos Limited | Wholesale & retail | 2025 |
| Solent Construction Limited | Construction | 1994 |
| Solent Contracting Limited | Construction | 2015 |
| Solent Court Management Company Limited | Households | 2005 |
| Solent Creative Home Solutions Ltd | Construction | 2026 |
| Solent Day Care C.I.C. | Health & social care | 2011 |
| Solent Dental Practice Limited | Health & social care | 2019 |
| Solent Design Ltd | Professional & scientific | 2016 |
| Solent Design Studio Limited | Manufacturing | 2003 |
| Solent Diesels Limited | Wholesale & retail | 2001 |
| Solent Drylining Limited | Construction | 2019 |
| Solent E-Scooter Repair Ltd | Manufacturing | 2023 |
| Solent Electrical Consultancy-Marine Limited | Construction | 2012 |
| Solent Electrical Limited | Construction | 1964 |
| Solent Engineering and IT Consultants Limited | Information & communication | 2012 |
| Solent Ergonomics Limited | Professional & scientific | 2015 |
| Solent Fibre Limited | Information & communication | 2018 |
| Solent Financial Ltd | Financial services | 2025 |
| Solent Financial Services Limited | Financial services | 2009 |
| Solent Fire and Electrical Services Ltd | Manufacturing | 2010 |
| Solent Flats Freehold Ltd | Households | 2024 |
| Solent Formwork Limited | Construction | 2007 |