| Kaikoura Leisure Ltd | Extraterritorial | 2023 |
| Kallista Electronics Limited | Administrative & support | 1998 |
| Kamcourt Limited | Real estate | 1998 |
| Kany Properties Ltd | Real estate | 2019 |
| KAS Maintenance Ltd | Construction | 2026 |
| Katie Bambro Ltd | Professional & scientific | 2013 |
| Kayko Limited | Real estate | 2017 |
| KDG Instruments Ltd | Information & communication | 2019 |
| Kdsg Property Limited | Households | 2024 |
| Keane Consultancy Services Limited | Professional & scientific | 2007 |
| Kebab & Go Limited | Hospitality | 2013 |
| Kelly Harrington Healthcare Consulting Limited | Health & social care | 2016 |
| Kelta HR Ltd | Administrative & support | 2006 |
| Kelta Solutions Ltd | Administrative & support | 2006 |
| Kemp Business Services Limited | Wholesale & retail | 2017 |
| Kennedy Damp Proofing Limited | Construction | 2025 |
| Kermacom Limited | Arts & recreation | 2009 |
| Keymer & Hassocks Mens Club Limited | Arts & recreation | 1995 |
| Keymer & Hassocks Sports & Social Club Limited | Arts & recreation | 2014 |
| Keymer Limited | Hospitality | 2024 |
| KG Investments South Ltd | Real estate | 2025 |
| KHS Holdings Ltd | Real estate | 2022 |
| Kian Hall Polo Ltd | Arts & recreation | 2016 |
| Kiddie Capers Childcare Ltd | Health & social care | 2018 |
| Kilostream Limited | Information & communication | 2000 |
| King Collective Limited | Other services | 2019 |
| Kingfisher (Essex) Ltd | Construction | 2025 |
| Kingstone Developments Ltd | Construction | 2003 |
| Kitchens DE LA Casa Limited | Wholesale & retail | 2017 |
| Kiyaar Properties Ltd | Real estate | 2015 |
| KKR Drinks Limited | Wholesale & retail | 2021 |
| Kore Advisory Ltd | Professional & scientific | 2025 |
| Kral Ltd | Hospitality | 2020 |
| Kris Cruisers LLP | | 2025 |
| Kris Townsend Ltd | Administrative & support | 2017 |
| Krzysztof Borkowski Ltd | Real estate | 2016 |
| KT Coatings Ltd | Construction | 2023 |
| Kudize Club Limited | Health & social care | 2016 |
| Kuwana Software Limited | Information & communication | 1994 |
| Kymarn Ltd | Professional & scientific | 2014 |
| L Mercer Construction Ltd | Construction | 2019 |
| L&A Manifestate Ltd | Real estate | 2023 |
| L&I Urban Estates Ltd | Real estate | 2025 |
| L'Auberdiere Services Limited | Wholesale & retail | 2014 |
| L.Electrical Contractors Limited | Construction | 2020 |
| L4ST Limited | Households | 2007 |
| LA Bouffe Ltd | Hospitality | 2015 |
| LA Fourchette Brasserie Ltd | Hospitality | 2017 |
| LA Fourchette Restaurant Worthing Ltd | Hospitality | 2025 |
| LA Galleria (Shoreham) Ltd | Hospitality | 2014 |
| LA Galleria (Sussex) Ltd | Real estate | 2011 |
| LA Tana Ltd | Hospitality | 2019 |
| Lackofafro Productions Ltd | Information & communication | 2009 |
| Lake Malawi Tourism Ltd | Administrative & support | 2023 |
| Lambe Inns Limited | Hospitality | 2003 |
| Land Management Services Limited | Professional & scientific | 1996 |
| Landscape Management Solutions Ltd | Agriculture & fishing | 2022 |
| Landscape Vision Ltd | Professional & scientific | 2003 |
| Lariday Properties Limited | Real estate | 2015 |
| Latitude Online Films Ltd | Arts & recreation | 2018 |
| Laura Jane RDH Ltd | Professional & scientific | 2019 |
| Lawnwood Limited | Real estate | 2001 |
| Lawrence One Limited | Wholesale & retail | 2026 |
| LCR Care 24 Ltd | Health & social care | 2016 |
| LE Palet Breton Ltd | Hospitality | 2017 |
| Leander International Kennels Limited | Other services | 1982 |
| Learning Cycle Consultancy Ltd | Education | 2009 |
| LEE Bealing Stonemasons Limited | Construction | 2006 |
| LEE Sullivan Contract Flooring Ltd | Construction | 2005 |
| Lema Tyres Limited | Wholesale & retail | 2022 |
| Lengah Investments Limited | Real estate | 2003 |
| Leonidas Brighton Ltd | Wholesale & retail | 2024 |
| Lexla Limited | Professional & scientific | 2022 |
| Lfcr Seven One Engineering Company Ltd | Construction | 2025 |
| Lhgh Ltd | Professional & scientific | 2020 |
| Licensed Decor UK Ltd | Wholesale & retail | 2024 |
| Lift One Ltd | Administrative & support | 2023 |
| Lightcastle Digital Limited | Wholesale & retail | 2025 |
| Limbach Limited | Wholesale & retail | 2012 |
| Lineworx Limited | Manufacturing | 2015 |
| Link House Healthcare Ltd | Health & social care | 2023 |
| Lisa's PUB Company Limited | Hospitality | 2018 |
| Little Bakers Ltd | Hospitality | 2019 |
| Little Bodhi Books Limited | Information & communication | 2012 |
| Little DON Movie Limited | Information & communication | 2013 |
| Little Goose Living Limited | Real estate | 2025 |
| Little Goose Ltd | Information & communication | 2019 |
| Little London Stud Limited | Agriculture & fishing | 2019 |
| Live and Learn Italian Ltd | Education | 2023 |
| Live Lucky Competitions Ltd | Wholesale & retail | 2026 |
| Livelihood London Ltd | Administrative & support | 2021 |
| LJ Russell Investment Ltd | Financial services | 2026 |
| LMC Consultancy Limited | Professional & scientific | 2003 |
| Local Emergency Plumber Ltd | Construction | 2023 |
| Lock in Skateboarding Ltd | Arts & recreation | 2025 |
| Lock Turner Ltd | Wholesale & retail | 2025 |
| London Gate Brighton Limited | Real estate | 2006 |
| Londonfoils Ltd | Wholesale & retail | 2020 |
| Longaeva Properties Ltd | Real estate | 2026 |
| Loose Ends Ltd | Real estate | 2023 |