| Sunkissed (Hove) Limited | Other services | 2024 |
| Supahosts Ltd | Professional & scientific | 2025 |
| Sureline Windows Limited | Construction | 2022 |
| Sussex Care Limited | Health & social care | 2024 |
| Sussex CNC Limited | Manufacturing | 2018 |
| Sussex Dolphin Project C.I.C. | Professional & scientific | 2023 |
| Sussex Fireplace Gallery Ltd | Wholesale & retail | 2009 |
| Sussex Footcare Ltd | Health & social care | 2025 |
| Sussex Housing Solutions Ltd | Real estate | 2020 |
| Sussex Lavender Ltd | Agriculture & fishing | 2023 |
| Sussex Ltd | Professional & scientific | 2015 |
| Sussex Marketing Ltd | Financial services | 2001 |
| Sussex Mobile Tyres Ltd | Wholesale & retail | 2025 |
| Sussex Pathways Limited | Administrative & support | 2008 |
| Sussex Sharpening Services Ltd | Other services | 2024 |
| Sussex Turnery & Moulding Company Limited | Manufacturing | 1975 |
| Swsp Developments Ltd | Real estate | 2023 |
| Sycamore Real Estate Ltd | Real estate | 2022 |
| Synapse Technical Recruitment Ltd | Information & communication | 2020 |
| Synetra Limited | Information & communication | 2025 |
| T & a Vision Limited | Administrative & support | 2011 |
| T Antonio Investments Ltd | Real estate | 2025 |
| TA Finance Ltd | Financial services | 2025 |
| Tagliare Advisory Limited | Professional & scientific | 2024 |
| Tagliare Capital Limited | Professional & scientific | 2024 |
| Tagliare Group Limited | Professional & scientific | 2024 |
| Talking Therapies Ltd | Health & social care | 2020 |
| Talosconsultants Ltd | Professional & scientific | 2019 |
| TAP Temporary Accommodation Providers Ltd | Real estate | 2019 |
| Tapifresh Limited | Manufacturing | 2015 |
| Tasty Burger Ltd | Hospitality | 2025 |
| Tavole Calde Ltd | Wholesale & retail | 2009 |
| Taxis 4 Hire Ltd | Transport & logistics | 2009 |
| Taxuk.Pl Ltd | Professional & scientific | 2022 |
| Taylor & SON Plastercraft Limited | Construction | 2023 |
| Taylor Contract Flooring Limited | Construction | 2013 |
| Taylor Holdings & Investments Ltd | Financial services | 2025 |
| Taylor Home Investments Ltd | Real estate | 2024 |
| Taylor Your Home Ltd | Real estate | 2022 |
| Taylor Your Home Solutions Ltd | Administrative & support | 2024 |
| Tayteck Limited | Information & communication | 2024 |
| TCD Trader Ltd | Wholesale & retail | 2017 |
| TCG Sourcing Ltd | Wholesale & retail | 2026 |
| Tech Therapy Ltd | Information & communication | 2011 |
| Technorbitals Ltd | Information & communication | 2013 |
| Tender Support UK Ltd | Professional & scientific | 2025 |
| Terre Rouge Ltd | Information & communication | 2022 |
| Tess Newall Limited | Manufacturing | 2023 |
| Thakeham Village Shop Management Ltd | Administrative & support | 2018 |
| THE Alma Uckfield Ltd | Hospitality | 2025 |
| THE Baker's Opera | Education | 2000 |
| THE Book Keepers Accounting and Payroll Services Limited | Professional & scientific | 2022 |
| THE British Society of Intraoperative Neurophysiology | Other services | 2015 |
| THE Cavalry Collective Ltd | Administrative & support | 2016 |
| THE Coffee Stop (Polegate) Limited | Hospitality | 2017 |
| THE Credible Communication Consultancy Limited | Professional & scientific | 2011 |
| THE Dressing Room (Alfriston) Limited | Wholesale & retail | 2017 |
| THE Eastbourne & District Preservation Trust Limited | Arts & recreation | 1965 |
| THE Fountain Cafe CIC | Hospitality | 2020 |
| THE Great Bridge of Knowledge Ltd | Education | 2025 |
| THE Great Curate Ltd | Information & communication | 2024 |
| THE Herball Ltd | Manufacturing | 2013 |
| THE Hogarth Consultancy Limited | Health & social care | 2016 |
| THE J Team Ltd | Professional & scientific | 2023 |
| THE Junction Polegate Limited | Other services | 2019 |
| THE Lamp Workshop Ltd | Other services | 2019 |
| THE Lamp Workshop Store Limited | Wholesale & retail | 2023 |
| THE Lawns (Tollwood Park) RTM Company Limited | Households | 2019 |
| THE Limes (Upperton) Limited | Households | 2003 |
| THE Oak Blokes Ltd | Construction | 2023 |
| THE Sanding Room Limited | Wholesale & retail | 2015 |
| THE Soil Factory CIC | Water & waste | 2025 |
| THE Sport Production Company Limited | Hospitality | 2009 |
| THE Sun Company (Horsham) Limited | Administrative & support | 2024 |
| THE Truggery Ltd | Manufacturing | 2022 |
| THE Tutoring School Ltd | Education | 2025 |
| THE UK Parking Group Limited | Real estate | 2021 |
| THE Vintage Motoring Company Limited | Transport & logistics | 2012 |
| Thebouncebee Ltd | Administrative & support | 2025 |
| Theclothingkings.Co.Uk Ltd | Manufacturing | 2023 |
| Theknowledgebridge Ltd | Professional & scientific | 2001 |
| Theraflo Ltd | Information & communication | 2026 |
| Thinksaydo Limited | Professional & scientific | 2003 |
| Thompson Rail Ltd | Construction | 2013 |
| Thoroughvent Limited | Professional & scientific | 2010 |
| Thoughtplay Ltd | Information & communication | 2004 |
| Thrive Production Music Ltd | Information & communication | 2020 |
| TID Technologies Limited | Administrative & support | 2025 |
| Tiger Advanced Limited | Real estate | 2023 |
| Timbertech Southern Limited | Construction | 2014 |
| Time Critical Consultancy Ltd | Wholesale & retail | 2023 |
| TJ SAW Ltd | Arts & recreation | 2025 |
| TKS Mini Market Ltd | Wholesale & retail | 2020 |
| TKS Stores Ltd | Wholesale & retail | 2025 |
| TNG Trading Limited | Wholesale & retail | 2014 |
| TNM Estates Ltd | Real estate | 2025 |
| TNM Holdings Ltd | Financial services | 2025 |
| Tnma Consulting Limited | Information & communication | 2014 |
| Together Therapy Ltd | Health & social care | 2010 |
| TOM Harris Brickwork Ltd | Construction | 2025 |