| HTG MAN & Van Ltd | Transport & logistics | 2025 |
| Hugo Davies Architect Ltd | Professional & scientific | 2023 |
| Human Rewilding Company Ltd | Professional & scientific | 2020 |
| Hunters Court Management Limited | Households | 1990 |
| Hunters Moon House Management Company Limited | Households | 2012 |
| Hutchcroft Limited | Professional & scientific | 2017 |
| Huxhams Cross Community Orchard Ltd | Agriculture & fishing | 2012 |
| Hydrosense Renewables Limited | Energy | 2012 |
| Hytech Surface Systems Ltd | Construction | 2023 |
| IAN Proctor Designs Limited | Professional & scientific | 1993 |
| Ice Comms Ltd | Information & communication | 2009 |
| Illuminatus Holdings Ltd | Manufacturing | 2026 |
| Imago Trading (SW) Limited | Wholesale & retail | 2015 |
| Imago Trading Holdings Ltd | Financial services | 2022 |
| IN Moderation Ltd. | Professional & scientific | 2020 |
| Inclusive Angels Limited | Other services | 2020 |
| Indian Kitchen Newton Abbot Limited | Hospitality | 2018 |
| Inner Seasons Ltd | Arts & recreation | 2016 |
| Innerclear Ltd | Health & social care | 2026 |
| Innobytez Ltd | Information & communication | 2024 |
| Integral Housing Ltd | Real estate | 2019 |
| Intelligent Information Limited | Information & communication | 1999 |
| Ireland Weller Limited | Real estate | 2000 |
| Ireland Weller Management Ltd | Real estate | 2024 |
| Iroko Wild Spa Limited | Arts & recreation | 2024 |
| Irpa 2026 (Liverpool) Limited | Administrative & support | 2023 |
| Island Village Cafe Limited | Hospitality | 2005 |
| Isos Living Ltd | Construction | 2013 |
| IST Simulations Ltd | Manufacturing | 2020 |
| IT Matters (Southwest) Limited | Health & social care | 2012 |
| ITG Finance Consulting Limited | Professional & scientific | 2019 |
| J & J Brewing Company Limited | Manufacturing | 2020 |
| J C Electrical Services (South West) Limited | Construction | 2009 |
| J.Mcintyre Properties Limited | Real estate | 2023 |
| Jack Jeffrey Associates Limited | Other services | 2004 |
| Jackson LEE Finance Ltd | Financial services | 2008 |
| Jackson-Lee Underwriting Limited | Extraterritorial | 1991 |
| JAJ Surveying Ltd | Professional & scientific | 2011 |
| Jamming Station C.I.C. | Arts & recreation | 2016 |
| Janlex Ltd | Real estate | 2021 |
| January Avenue Limited | Professional & scientific | 2016 |
| JAY Clements Contracting Limited | Agriculture & fishing | 2023 |
| Jc-Yachts Limited | Administrative & support | 2024 |
| JCP Property Management Ltd | Real estate | 2023 |
| JD Woods Property Management Limited | Real estate | 2024 |
| Jedi Motorcycle Training Ltd | Education | 2025 |
| Jemtx Limited | Manufacturing | 2008 |
| Jenasuni Limited | Financial services | 2014 |
| Jennifer ANN Homes Limited | Construction | 2013 |
| Jeremy Grove Limited | Professional & scientific | 2011 |
| Jihan Adem Ltd | Education | 2014 |
| Jin@Paperworks Limited | Arts & recreation | 2015 |
| JKR Electrical Services Limited | Construction | 2005 |
| JOE Cook DOP Ltd. | Information & communication | 2015 |
| John Clements Contractors Ltd | Construction | 2014 |
| John Life Engineering Limited | Professional & scientific | 2022 |
| John Payne Plumbing and Heating Limited | Other services | 2008 |
| JON Cole Mortgages Ltd | Financial services | 2022 |
| Jorgensen (UK) Limited | Extraterritorial | 2013 |
| Josie Dayment Bookkeeping Ltd | Professional & scientific | 2025 |
| Joy Persephone Ltd | Education | 2026 |
| JR Surgery Limited | Health & social care | 2022 |
| Jumping Mouse Ltd | Information & communication | 2004 |
| Just Beautiful Floors Ltd | Wholesale & retail | 2022 |
| Justeel Limited | Administrative & support | 1991 |
| K Borska Ltd | Health & social care | 2014 |
| Kachet Cleaning Ltd | Administrative & support | 2016 |
| Kairos House Residential Ltd | Hospitality | 2025 |
| Kankon Projects Ltd | Construction | 2026 |
| Kasimo Limited | Real estate | 2001 |
| Kell Gear Ltd | Professional & scientific | 2020 |
| Kelland Superstructures Ltd | Construction | 2022 |
| Kente UK Ltd | Wholesale & retail | 2019 |
| Kentech Contract & Construction Services Ltd | Other services | 2009 |
| Kevin IAN Hare Limited | Administrative & support | 2024 |
| Kevin Maddocks Ltd | Construction | 2018 |
| Key Cover Services Limited | Financial services | 2017 |
| Keystone Property Management Limited | Construction | 2004 |
| Keziah Critchlow-Salisbury Limited | Professional & scientific | 2022 |
| Kibco Holdings Ltd | Real estate | 2022 |
| Kindbot Limited | Professional & scientific | 2021 |
| Kingsbridge Auto Repair & Rescue Ltd | Wholesale & retail | 2003 |
| Kingsbridge MOT Centre Ltd | Wholesale & retail | 2023 |
| Kingsbridge Taverns Limited | Hospitality | 2006 |
| Kirkcaldy Bell Ltd | Education | 2023 |
| Kith and KIN Network CIC | Education | 2010 |
| Kitley Self Storage Ltd | Real estate | 2021 |
| Kitty Kimber Ltd | Manufacturing | 2024 |
| Kmac Recycling Limited | Extraterritorial | 2016 |
| KMT48 Limited | Hospitality | 2011 |
| Knead Peace Limited | Hospitality | 2024 |
| Knead Pizza Ltd | Hospitality | 2017 |
| Knowle Tree Services Limited | Agriculture & fishing | 2008 |
| KPW Newkey Ltd | Administrative & support | 2009 |
| Kyac Ltd | Manufacturing | 2020 |
| L&G Accountancy Limited | Professional & scientific | 2025 |
| Labours of Hercules Ltd | Information & communication | 2018 |
| Lancaster and Gibbings Ltd | Arts & recreation | 2017 |
| Landcraft Projects Limited | Construction | 1992 |
| Langham O'Hea Limited | Administrative & support | 2023 |