| LG Roofing Services. Ltd | Construction | 2024 |
| LGC Landscaping Limited | Administrative & support | 2019 |
| Lhec Assets Limited | Real estate | 2022 |
| LIA Hatz Limited | Financial services | 2019 |
| Liam James KAY Ltd | Professional & scientific | 2018 |
| Liberty Brands Ltd | Hospitality | 2026 |
| LIBERTY842 Ltd | Information & communication | 2009 |
| Libra Investments & Holdings Ltd | Real estate | 2024 |
| Lifestyle Property Solutions Ltd | Construction | 2017 |
| Lifetime Finance Ltd | Financial services | 2009 |
| Liggins Wainewright Architecture Ltd | Professional & scientific | 2016 |
| Light Architecture Ltd | Construction | 2000 |
| Likwid Wavesports Ltd | Arts & recreation | 2020 |
| LIL Wabbit Limited | Manufacturing | 2020 |
| Lily Langmead Ltd | Arts & recreation | 2024 |
| Lily Supply Ltd | Wholesale & retail | 2026 |
| Lilybud Gardens by Design Brighton Limited | Other services | 2010 |
| Limbo Designs Limited | Administrative & support | 2003 |
| Limbrick Corner Estates Ltd | Real estate | 2024 |
| Lime Green Homebuyers Limited | Real estate | 2010 |
| Lime Tree Close Developments Ltd | Construction | 2019 |
| Limelight UK Events Ltd | Professional & scientific | 2022 |
| Lindfield Living Limited | Real estate | 2025 |
| Lindfield Logistics Limited | Transport & logistics | 2022 |
| Lindsay FIC | Financial services | 2023 |
| Lingfield Gardens Management Company Ltd | Real estate | 2022 |
| Linked Inside Learning CIC | Education | 2026 |
| Linko Construction Limited | Construction | 2017 |
| Linx Studio Limited | Professional & scientific | 2018 |
| Lion Consultancy Group Limited | Real estate | 2019 |
| Lion Property Group UK Limited | Real estate | 2016 |
| Lion Sejant Consulting Ltd | Administrative & support | 2017 |
| Lionel House (Worthing) Limited | Health & social care | 1999 |
| Lionheart Productions Ltd | Information & communication | 2023 |
| Lions Mane Roofing Limited | Construction | 2026 |
| Liotru Limited | Hospitality | 2011 |
| Liqui Group Limited | Professional & scientific | 2016 |
| Liquid Trading Systems Limited | Financial services | 2017 |
| Lisa Sarjeant Associates Ltd | Administrative & support | 2015 |
| Lisden Physiotherapy Clinic Limited | Arts & recreation | 2003 |
| Lisgo-Charlton Limited | Real estate | 1994 |
| Listen Hearing Care Limited | Wholesale & retail | 2018 |
| Lister West Associates Limited | Professional & scientific | 2017 |
| Lister West Estates Limited | Real estate | 2020 |
| Lite Group Limited | Hospitality | 2017 |
| Lithsafe Ltd | Professional & scientific | 2024 |
| Little Blue Dog Limited | Information & communication | 2015 |
| Little Box of Crochet Ltd | Manufacturing | 2022 |
| Little Episodes Productions Limited | Information & communication | 2018 |
| Little Fledglings Nursery Ltd | Education | 2022 |
| Little HUT Studios Limited | Arts & recreation | 2021 |
| Little Nestlings Nursery (Shoreham) Ltd | Health & social care | 2019 |
| Little Paddocks Freeholders Limited | Real estate | 1973 |
| Little Spatham Farm LLP | | 2023 |
| Little Stones Pre-School Limited | Education | 2020 |
| Little Tums Catering Ltd | Manufacturing | 2018 |
| Little Wolf Cubic Creations Ltd | Wholesale & retail | 2024 |
| Littlehampton Heritage Railway Ltd | Information & communication | 2016 |
| Littlehampton Sportsfield | Extraterritorial | 2010 |
| Live and Roar Design Limited | Professional & scientific | 2012 |
| Live Outdoors Ltd | Wholesale & retail | 2018 |
| Live the Adventure Club Limited | Professional & scientific | 2017 |
| Lively Treasures Limited | Wholesale & retail | 2024 |
| Livikan Limited | Wholesale & retail | 2025 |
| Living Interiors Limited | Wholesale & retail | 2010 |
| Living Sports Limited | Information & communication | 2011 |
| Living Your Best Life Limited | Arts & recreation | 2018 |
| Livingstone Club Limited | Other services | 2024 |
| LIZ Beresford Psychotherapy Limited | Health & social care | 2025 |
| Lizzy Bizzy Ltd | Information & communication | 2024 |
| LJ Consultants Ltd | Professional & scientific | 2025 |
| LJC Plumbing & Heating Ltd | Construction | 2018 |
| LJK Sales & Marketing Limited | Wholesale & retail | 2002 |
| LJM Electrical Services Limited | Construction | 2019 |
| LJP Management Ltd | Administrative & support | 2021 |
| Llandaff Court Tenants Association Limited | Households | 1961 |
| Lloyd Lindsey Ltd | Real estate | 2017 |
| Lloyd Metal Spinners Ltd | Manufacturing | 2009 |
| LMA Health Limited | Health & social care | 2023 |
| LMC Auto Services (Sussex) Limited | Wholesale & retail | 2014 |
| Lmmcc Ltd | Professional & scientific | 2020 |
| LMQ Property Management Ltd | Real estate | 2020 |
| LMR Media Ltd | Information & communication | 2025 |
| LMY Services Ltd | Hospitality | 2020 |
| LNH Holdings Ltd | Real estate | 2021 |
| Local Toilet Hire Ltd. | Administrative & support | 2014 |
| Lock and Lindfield Limited | Construction | 2017 |
| Lock G & R Limited | Financial services | 2017 |
| Lock IP Limited | Financial services | 2011 |
| Locnet Limited | Professional & scientific | 2008 |
| Locomotive Inn Flats Limited | Households | 2022 |
| Lodge’S Lockups Limited | Other services | 2024 |
| Loecare Ltd | Health & social care | 2023 |
| Lofie Realty Limited | Real estate | 2025 |
| Loftworks KJ Ltd | Construction | 2024 |
| Logical Sense Limited | Manufacturing | 2004 |
| Logicel Consultants Limited | Professional & scientific | 1998 |
| Logimate Group Ltd | Wholesale & retail | 2026 |
| Lognet Information Systems Limited | Information & communication | 2006 |
| Logos Computer Services Limited | Information & communication | 1992 |