| KT ALB Transport Limited | Transport & logistics | 2015 |
| KT Displays Ltd | Information & communication | 2009 |
| KT Family Solicitors Limited | Professional & scientific | 2015 |
| Ktmm Hub Ltd | Wholesale & retail | 2024 |
| Kube Holdings SW Limited | Financial services | 2022 |
| Kube Medical Limited | Health & social care | 2008 |
| Kubera Treats Limited | Manufacturing | 2020 |
| Kubus Polski Manchester Road Ltd | Wholesale & retail | 2026 |
| Kubus Polski Swindon Ltd | Wholesale & retail | 2025 |
| Kudos Fencing Limited | Construction | 2004 |
| KUK Sool WON of Liverpool Ltd | Arts & recreation | 2016 |
| Kulmaine Limited | Real estate | 2024 |
| Kumba Properties Ltd | Real estate | 2021 |
| Kunta Professional Services Ltd | Construction | 2017 |
| Kurdish Barber Swindon Ltd | Other services | 2024 |
| Kusang Ltd | Real estate | 2025 |
| Kushaya Health Care Ltd | Health & social care | 2026 |
| KVK Property Limited | Real estate | 2025 |
| KVR Consultancy Ltd | Professional & scientific | 2025 |
| KW Plant Services Ltd | Manufacturing | 2024 |
| Kwabs Mpharm Ltd | Professional & scientific | 2023 |
| Kwad UK Ltd | Health & social care | 2012 |
| Kwirky KOW Vintage Limited | Wholesale & retail | 2024 |
| Kwoyaa Ltd | Health & social care | 2021 |
| KWS Hairdressing Limited | Other services | 2006 |
| Kyodais Ltd | Real estate | 2025 |
| Kyratfit Ltd | Arts & recreation | 2025 |
| Kyrie Consulting Limited | Professional & scientific | 2024 |
| Kyte's Building Contractors Limited | Administrative & support | 2014 |
| KZ Auto Export Ltd | Wholesale & retail | 2025 |
| KZ181 Ltd | Hospitality | 2024 |
| L & a Cleaning Services Swindon Ltd | Administrative & support | 2024 |
| L & C Cleaning Ltd | Administrative & support | 2009 |
| L & D Services (Swindon) Ltd | Administrative & support | 2014 |
| L & E Grange Limited | Construction | 2013 |
| L & R Automotive Ltd | Wholesale & retail | 2023 |
| L & S Postal Services Ltd | Transport & logistics | 2021 |
| L & V Care UK Limited | Health & social care | 2015 |
| L Andrei Transport Limited | Transport & logistics | 2025 |
| L Costello Ltd | Education | 2023 |
| L D Electrical Solutions Ltd | Construction | 2014 |
| L D J Associates Ltd | Real estate | 2019 |
| L E Electrical (Cirencester) Ltd | Construction | 2024 |
| L Johnston Contractors Ltd | Construction | 2019 |
| L K Industrial Services Ltd | Construction | 2020 |
| L M Hotfoil Limited | Manufacturing | 2010 |
| L R S Cleaning Services Ltd | Administrative & support | 2025 |
| L Squared Solutions Limited | Professional & scientific | 2011 |
| L Swindon Motors Ltd | Wholesale & retail | 2025 |
| L Walsh Ltd | Health & social care | 2016 |
| L&C Masters Cleaning Service Ltd | Administrative & support | 2024 |
| L&D Nails Limited | Other services | 2019 |
| L&P Facades Ltd | Construction | 2025 |
| L&P Nominees Limited | Extraterritorial | 2001 |
| L&R Facilities Solutions Ltd | Wholesale & retail | 2019 |
| L&S Autos Mobile Mechanic Limited | Wholesale & retail | 2019 |
| L&S Silver Lining Studios Ltd | Other services | 2017 |
| L&T Consultancy Ltd | Administrative & support | 2018 |
| L&T Contracting Limited | Transport & logistics | 2021 |
| L&W Property Investments Ltd | Real estate | 2022 |
| L' Computer Hub (UK) Limited | Other services | 2017 |
| L.A. Plumbing & Heating (Swindon) Limited | Construction | 2014 |
| L.E.D. Lighting Design Limited | Professional & scientific | 2000 |
| L.K.Skips Limited | Water & waste | 2014 |
| L.O.G Cosmetics Ltd | Wholesale & retail | 2014 |
| L3BRON3 Limited | Administrative & support | 2010 |
| LA Beauté Ltd | Other services | 2017 |
| LA Carbonara Limited | Hospitality | 2010 |
| LA Cerise Limited | Wholesale & retail | 2024 |
| LA Jacobs Ltd | Hospitality | 2024 |
| LA Massana Limited | Administrative & support | 2017 |
| LA Migra INK Tattooshop Ltd | Other services | 2019 |
| LA Nostalgia Ltd | Hospitality | 2013 |
| LA Pasta Parade Ltd | Manufacturing | 2024 |
| LA Pizza Pazza Ltd | Hospitality | 2019 |
| LA Plates Limited | Manufacturing | 2024 |
| Laay Limited | Health & social care | 2018 |
| Lacey’S Development Ltd | Construction | 2025 |
| Laderach (UK) Limited | Wholesale & retail | 2019 |
| Ladwa Law Limited | Professional & scientific | 2024 |
| Lady Margaret Flats Management Co. Ltd. | Households | 1985 |
| Ladysmith Equestrian Centre Limited | Arts & recreation | 2014 |
| Lagos 99 Limited | Hospitality | 2025 |
| Laguna Design Ltd | Wholesale & retail | 2011 |
| Laidlaw Education Group LLP | | 2016 |
| LAK (Melksham) Ltd | Hospitality | 2021 |
| Lake Ascend Ltd | Education | 2023 |
| Lake Langley Associates Limited | Extraterritorial | 2007 |
| Lakeside Carpentry and Building Services Limited | Construction | 2020 |
| Lakeside Construction Group Limited | Construction | 2021 |
| Lakeside Kitchens & Bathrooms Ltd | Construction | 2026 |
| Lakeside Properties (South) Limited | Real estate | 2023 |
| Lakeview Holidays Ltd | Hospitality | 2018 |
| Lakmed Limited | Wholesale & retail | 2025 |
| Lakshay Infotech UK Limited | Information & communication | 2006 |
| Lalezar Limited | Hospitality | 2023 |
| Lamara Developments Ltd | Real estate | 2025 |
| Lambourn Catering Butchers Limited | Manufacturing | 2022 |
| Lambrook Partners LLP | | 2025 |
| Lamelo UK Limited | Other services | 2020 |