| Simpson & Associates (Accountants) Limited | Professional & scientific | 2011 |
| Simpsons Car Rental Ltd | Administrative & support | 2024 |
| Sims Autos Mobile Tyre Service Limited | Wholesale & retail | 2025 |
| Simsim Bournemouth 2 Ltd | Hospitality | 2021 |
| Simsim Bournemouth Ltd | Financial services | 2021 |
| SIN Tribu Ltd | Extraterritorial | 2026 |
| Sinclair Court Management (Parkstone) Limited | Households | 1989 |
| Sindbad Restaurant Ltd | Hospitality | 2025 |
| Sinewave Electrical Contractors Ltd | Construction | 2023 |
| Sinewave Holdings Limited | Financial services | 2026 |
| Sinstone Limited | Wholesale & retail | 2025 |
| Siora Fragrances Ltd | Manufacturing | 2025 |
| SIP & Lips Glow Ltd | Hospitality | 2026 |
| Siprea Design Limited | Information & communication | 2019 |
| SIR Enterprises Limited | Professional & scientific | 2004 |
| SIR Peter Thompson House Limited | Households | 2011 |
| SIR Pizza Ltd | Hospitality | 2025 |
| Siso Limited | Hospitality | 2025 |
| Sitaram Transport CIC | Transport & logistics | 2026 |
| Site Manager Pro Limited | Information & communication | 2024 |
| Site Seekers Limited | Construction | 2006 |
| Site Services Southern Limited | Administrative & support | 2022 |
| Site Space Limited | Professional & scientific | 2017 |
| Sitoria Healthcare Group Limited | Health & social care | 2025 |
| SIV Dorset Ltd | Other services | 2022 |
| SJ Handcarwash Limited | Administrative & support | 2018 |
| SJ Hire Limited | Administrative & support | 2023 |
| SJ Roofers Ltd | Construction | 2021 |
| SJ Site Services (Dorset) Ltd | Construction | 2019 |
| SJC Bournemouth RTM Company Limited | Households | 2026 |
| SJC Chiropractic Ltd | Health & social care | 2023 |
| SJC Fuel Services Limited | Wholesale & retail | 2024 |
| SJH Rentals Ltd | Real estate | 2021 |
| Sjjs Solutions Limited | Professional & scientific | 2020 |
| Sjmd Holdings Ltd | Real estate | 2019 |
| Sjmd Rentals Ltd | Real estate | 2019 |
| Sjmi Properties Limited | Real estate | 2022 |
| Sjpb Holdings Ltd | Financial services | 2025 |
| Sjprc Ltd | Financial services | 2019 |
| SJR Logistics Ltd | Transport & logistics | 2024 |
| SJR Properties Dorset Limited | Real estate | 2025 |
| SJS Industrial Projects Limited | Construction | 2015 |
| Sjscratches Ltd | Other services | 2024 |
| Sjsmiles Ltd | Health & social care | 2025 |
| SJT Accounts Ltd | Professional & scientific | 2014 |
| SK ELM Property Ltd | Real estate | 2026 |
| SK General Store Ltd | Wholesale & retail | 2024 |
| SK Heating and Cooling Solutions Ltd | Construction | 2026 |
| SK Survey Limited | Professional & scientific | 2016 |
| SKC (South) Ltd | Real estate | 2015 |
| Skerryvore Court Management Company Limited | Real estate | 2003 |
| Sketch HQ Limited | Construction | 2019 |
| Skeventmanaging Ltd | Hospitality | 2025 |
| SKG Dyna Ltd | Wholesale & retail | 2018 |
| Skibinscy Company Ltd | Transport & logistics | 2020 |
| Skill Build Consultancy Limited | Construction | 2024 |
| Skill Touch Ltd | Manufacturing | 2023 |
| Skills for Jobs Group Ltd | Education | 2019 |
| Skillspire Education Ltd | Education | 2025 |
| Skin Bureaux Limited | Wholesale & retail | 2022 |
| Skin Gym Cosmetics Ltd | Other services | 2019 |
| Skin Health and Beauty Aesthetic Clinic Bournemouth Ltd | Education | 2023 |
| Skin Zest Limited | Other services | 2024 |
| Skinlight Esthetical Ltd | Wholesale & retail | 2024 |
| Skinny Malinkys (Southbourne) Limited | Hospitality | 2025 |
| SKM Carpentry Ltd | Construction | 2019 |
| SKM Northmere Ltd | Construction | 2018 |
| SKN Gifts Limited | Wholesale & retail | 2019 |
| Skoobie Digital Marketing Ltd | Professional & scientific | 2023 |
| Skoobie Ltd | Other services | 2021 |
| Skrus Ltd | Transport & logistics | 2016 |
| SKW Contracts Ltd | Construction | 2019 |
| Sky Accounting Limited | Professional & scientific | 2010 |
| Sky Blue Distribution Limited | Wholesale & retail | 2019 |
| Sky Composites Limited | Manufacturing | 2021 |
| Skybeds Ltd | Wholesale & retail | 2025 |
| Skybridge IT Limited | Information & communication | 2025 |
| Skybridge Transport Ltd | Wholesale & retail | 2026 |
| Skybus Homes Limited | Real estate | 2022 |
| Skybus Limited | Construction | 2013 |
| Skycab Limited | Transport & logistics | 1982 |
| Skycatch Logistics Ltd | Transport & logistics | 2025 |
| Skye Deck (Dorset) Ltd | Professional & scientific | 2023 |
| Skye Holdings (Dorset) Ltd | Financial services | 2019 |
| Skye Scaffolding (Dorset) Ltd | Construction | 2018 |
| Skye Scaffolding Southern Ltd | Construction | 2023 |
| Skyhunter Aerospace Flight Test and Evaluation Ltd | Manufacturing | 2021 |
| Skylark Close Management Company Limited | Households | 2022 |
| Skylark Flight Training Ltd | Professional & scientific | 2023 |
| Skyler Formwork Limited | Construction | 2019 |
| Skylight Property Maintenance Services Ltd | Construction | 2022 |
| Skyray Holdings Ltd | Financial services | 2026 |
| Skyrocket Talent Ltd | Professional & scientific | 2015 |
| Slade & Slade Limited | Real estate | 2024 |
| Slade Farrell Properties Ltd | Real estate | 2022 |
| Slades Commercial Ltd | Real estate | 2024 |
| Slades Lets Limited | Real estate | 2003 |
| Slagor Ltd | Professional & scientific | 2021 |
| Slam Property (Bournemouth) Limited | Real estate | 2025 |
| Slav V Service Ltd | Construction | 2022 |