| Jsas Web Services Ltd | Information & communication | 2012 |
| Jukecarpentry Ltd | Manufacturing | 2025 |
| Juliet Foods Ltd | Wholesale & retail | 2018 |
| Juty Ltd | Hospitality | 2022 |
| K & G Contractors (Sussex) Limited | Construction | 2024 |
| K.W.T Printing Services Limited | Information & communication | 1975 |
| KA Distribution Limited | Wholesale & retail | 2023 |
| KA Strategic Consultancy Ltd | Professional & scientific | 2026 |
| Kabra Properties Ltd | Real estate | 2021 |
| Kailok Limited | Real estate | 2020 |
| Kalamaki Food Truck Ltd | Hospitality | 2025 |
| Kaplev Ltd | Wholesale & retail | 2025 |
| KBE Build Ltd | Construction | 2023 |
| KBS Renovations Ltd | Construction | 2023 |
| KCT Osteopathy Limited | Health & social care | 2022 |
| Kedgwynne Capital Ltd | Financial services | 2026 |
| Kedgwynne Holdings Ltd | Financial services | 2026 |
| Keen & Simpson Builders Limited | Construction | 2019 |
| Kent M&E Group Limited | Professional & scientific | 2019 |
| Kestan 23 Ltd | Real estate | 2010 |
| Kibbsy Limited | Arts & recreation | 2023 |
| Kids Stuff for Less Ltd | Wholesale & retail | 2018 |
| Killy Limited | Financial services | 2017 |
| Kin&Co Enterprises Limited | Professional & scientific | 2015 |
| Kin&Collective Limited | Financial services | 2024 |
| Kings Reach Limited | Health & social care | 2008 |
| Kings Reach Trading Limited | Public administration | 2003 |
| Kirolous George Sobhi Habieb Ltd | Transport & logistics | 2024 |
| Kitchens & Furniture Sprayed Colourfull Ltd | Other services | 2024 |
| KJS Independent Ltd | Health & social care | 2026 |
| KM Claims & Consulting Limited | Financial services | 2020 |
| Knightguard Security Ltd | Administrative & support | 2009 |
| Kochev BG Trans Ltd | Transport & logistics | 2020 |
| Kolo Foods Ltd | Wholesale & retail | 2018 |
| Kpms Limited | Construction | 2009 |
| KPS Electrical Limited | Construction | 2012 |
| KR Carpentry & Building Ltd | Construction | 2019 |
| KS Print Ltd | Manufacturing | 2018 |
| KWT Properties Ltd | Real estate | 2022 |
| Kyan & Teddy Limited | Wholesale & retail | 2024 |
| L & Z Investments Limited | Real estate | 2022 |
| L and M Carpentry Limited | Construction | 2010 |
| L Pizzanightplus Ltd | Hospitality | 2024 |
| L&G Home Solutions Ltd | Construction | 2025 |
| L.B.Longley Investments Limited | Real estate | 1955 |
| Lamin Web Consultancy Ltd | Information & communication | 2022 |
| Lancing Business Park Limited | Real estate | 2003 |
| Lancing College Preparatory School at Worthing Limited | Education | 2013 |
| Lancing Electrical Services Ltd | Construction | 2017 |
| Lancing Football Club Ltd | Arts & recreation | 2026 |
| Lancing Greetings Ltd | Wholesale & retail | 2019 |
| Lancing Medical Limited | Wholesale & retail | 2024 |
| Lancing Nails Limited | Other services | 2023 |
| Lancing Personal Training Ltd | Arts & recreation | 2025 |
| Lancing Rangers & Sompting FC C.I.C. | Arts & recreation | 2021 |
| Lancing Takeaway Limited | Hospitality | 2023 |
| Lancing United FC Limited | Arts & recreation | 2014 |
| Landcorp Developments Ltd | Real estate | 2006 |
| Landmark AMG Limited | Construction | 2020 |
| Lane Personnel Ltd | Other services | 2015 |
| Lantern House (Padstow) Limited | Households | 2017 |
| Larkspur (Lancing) Management Limited | Households | 1993 |
| LB Bike Parts Ltd | Wholesale & retail | 2020 |
| LDT Landscaping Ltd | Professional & scientific | 2025 |
| Leaneys of Lancing Limited | Wholesale & retail | 1964 |
| Learning Holidays Limited | Education | 2022 |
| Leco Rotterdam Limited | Hospitality | 2024 |
| Leegal Limited | Professional & scientific | 2022 |
| Leek Ltd | Professional & scientific | 2023 |
| Legacy Golf Ltd | Professional & scientific | 2020 |
| Leghall Limited | Professional & scientific | 2013 |
| Leslie J. Thorpe Limited | Construction | 1985 |
| LF Aviation Limited | Transport & logistics | 2010 |
| Lidgate Systems Ltd | Information & communication | 2025 |
| Lifetrain UK Limited | Education | 2001 |
| Lifted Reach Ltd | Arts & recreation | 2024 |
| Lighthouse Design Studio Ltd | Professional & scientific | 2024 |
| Lighttouch AV Limited | Administrative & support | 2023 |
| Limelight Networks Ltd | Other services | 2006 |
| Links on TAP Ltd | Professional & scientific | 2025 |
| Lisher Personnel and Healthcare Limited | Administrative & support | 2014 |
| Living HER Best Life Limited | Arts & recreation | 2021 |
| LIW Beauty Ltd | Manufacturing | 2016 |
| LJM Lettings Ltd | Real estate | 2024 |
| LLC Rigging Ltd | Construction | 2025 |
| LN Project Consultancy Ltd | Professional & scientific | 2012 |
| Local Alliance Partnership CIC | Other services | 2025 |
| Loci London Limited | Information & communication | 2009 |
| London and Victoria Realty Investments Ltd | Real estate | 2025 |
| London Block Ltd | Construction | 2020 |
| London Gold and Collectibles Ltd | Wholesale & retail | 2024 |
| Lotus Equities Limited | Real estate | 2007 |
| Lovett Creations Limited | Wholesale & retail | 2023 |
| LUKIE16 Limited | Professional & scientific | 2021 |
| Lurez Ltd | Wholesale & retail | 2025 |
| Luxor Beauty Lounge Ltd | Other services | 2019 |
| Luxor Freehold Ltd | Households | 2020 |
| Luxury Travel Diary Limited | Other services | 2014 |
| M Christou Holdings Limited | Financial services | 2026 |
| M P Property Management (Sussex) Ltd | Construction | 2025 |