| Intanest Limited | Information & communication | 2019 |
| Intastop Group Limited | Manufacturing | 2018 |
| Intastop Holdings Limited | Financial services | 2016 |
| Intastop Installations Ltd | Manufacturing | 2016 |
| Intastop Limited | Manufacturing | 1985 |
| Integra (Angus Nordon) Ltd | Professional & scientific | 2023 |
| Integra (Yorkshire) Ltd | Professional & scientific | 2018 |
| Integrated Fire and Security Ltd | Administrative & support | 2015 |
| Integrated Marketing Services Limited | Transport & logistics | 2015 |
| Interact Limited | Manufacturing | 1992 |
| Ionascu Limited | Transport & logistics | 2025 |
| IPF Consultancy Limited | Professional & scientific | 2021 |
| Iron Dram Ltd | Hospitality | 2020 |
| Isaquinn Developments Ltd | Financial services | 2026 |
| Isophase Audio Limited | Administrative & support | 2011 |
| Italian Leather Limited | Wholesale & retail | 2023 |
| Itransport WY Ltd | Transport & logistics | 2023 |
| ITS Bliss Limited | Wholesale & retail | 2004 |
| IVY Care Falls Response Ltd | Health & social care | 2026 |
| IVY Care Group Ltd | Health & social care | 2025 |
| IVY Care Services Ltd | Health & social care | 2023 |
| IVY Cottage Trading Ltd | Construction | 2025 |
| Ivy's Homecare Services Limited | Health & social care | 2025 |
| Izkhomeremoval Limited | Transport & logistics | 2025 |
| J & J Electrical Castleford Limited | Manufacturing | 2023 |
| J & M Builders (Yorkshire) Limited | Construction | 2011 |
| J and K Ismay Decorators Ltd | Construction | 2023 |
| J B Heating Solutions Limited | Construction | 2022 |
| J C Trucks & Cranes Ltd | Construction | 2014 |
| J Cuttle Estates Ltd | Real estate | 2026 |
| J England Logistics Ltd | Transport & logistics | 2026 |
| J Lloyd Security Limited | Administrative & support | 2016 |
| J M Developments Yorkshire Limited | Construction | 2023 |
| J M Richardson (Farming) Limited | Agriculture & fishing | 1962 |
| J Marr (Property) Limited | Real estate | 2002 |
| J Poulson Agile Services Ltd | Information & communication | 2025 |
| J Shepherd Freelance Hair Limited | Other services | 2017 |
| J Willey & Co Limited | Financial services | 2015 |
| J&D Civil Engineering Ltd | Construction | 2022 |
| J&J Forecourt Ltd | Wholesale & retail | 2017 |
| J&R Property Enterprises Ltd | Real estate | 2026 |
| J&T Groundworks & Utilities Ltd | Construction | 2023 |
| J. Horobin Gardening Services Ltd. | Other services | 2003 |
| J. Marr Limited | Professional & scientific | 1902 |
| J.L.Machinery Ltd | Wholesale & retail | 2019 |
| J.P.C. Developments (Yorkshire) Limited | Construction | 2009 |
| J.W.O. Media Limited | Information & communication | 2006 |
| JA & NR Services Ltd | Construction | 2021 |
| Jackman Walker Limited | Construction | 2013 |
| Jaflong Elmsall Ltd | Hospitality | 2023 |
| Jagagi Ltd | Hospitality | 2025 |
| Jagholidays Ltd | Real estate | 2025 |
| Jake Robson Limited | Construction | 2012 |
| Jamac Property & Investment Ltd | Real estate | 2019 |
| James Finnie & SON Ltd | Arts & recreation | 2023 |
| James Lomas & SON Properties Limited | Construction | 2006 |
| Jamie’S Wardrobe Ltd | Wholesale & retail | 2026 |
| Jamzz Ltd | Wholesale & retail | 2018 |
| Jane Nova Technology Ltd | Wholesale & retail | 2025 |
| Janes Properties Limited | Real estate | 1999 |
| Jansar Ltd | Households | 2025 |
| JARGA12 Ltd | Other services | 2024 |
| Jarvis AI Ltd | Information & communication | 2026 |
| Jasmine Court (WF7) RTM Company Limited | Households | 2024 |
| Jason Flay Installations Ltd | Construction | 2021 |
| Jasper's Bar Ltd | Hospitality | 2025 |
| Javadrive Ltd | Transport & logistics | 2019 |
| Javn Investment Ltd | Wholesale & retail | 2026 |
| Jazzcnc Ltd | Other services | 2018 |
| JB Governance Consultancy Ltd | Professional & scientific | 2023 |
| JB Vent Supplies Ltd | Wholesale & retail | 2025 |
| JBE Sports Consulting Limited | Arts & recreation | 2019 |
| JC Electrical and Refrigeration Services Ltd | Construction | 2022 |
| JC One Promotions Ltd | Information & communication | 2011 |
| JCL2026 Ltd | Real estate | 2026 |
| JCM Engineering Ltd | Professional & scientific | 2025 |
| JD Mobile Sandblasting Ltd | Construction | 2025 |
| JDD Insulation Limited | Construction | 1999 |
| JDI FAR East Ltd | Professional & scientific | 2015 |
| JDI North Yorkshire Limited | Real estate | 2024 |
| JDL Consulting Limited | Professional & scientific | 2023 |
| JDO Solutions Ltd | Information & communication | 2025 |
| JDP Educational Consultant Ltd | Education | 2016 |
| Jeavons Ltd | Real estate | 2025 |
| Jenine Hunter Limited | Real estate | 2021 |
| Jenkin Halls Recruitment Limited | Administrative & support | 2008 |
| Jennifer Craven Ltd | Professional & scientific | 2026 |
| Jenroe Financial Solutions Ltd | Financial services | 2022 |
| Jesse Jackson Hair Ltd | Other services | 2025 |
| Jessica Gamlin Ltd | Education | 2024 |
| Jesters Gymnastics Club Ltd | Arts & recreation | 2018 |
| JET Mortgages Ltd | Financial services | 2024 |
| JET Sign and Graphics Limited | Construction | 2025 |
| JET Signs and Graphics Limited | Professional & scientific | 2022 |
| Jetaway Drainage Solutions Ltd | Water & waste | 2021 |
| JFD (Yorkshire) Limited | Construction | 2025 |
| JFS Homes Ltd | Real estate | 2025 |
| JFU Partnerships Limited | Information & communication | 2012 |
| Jirc Limited | Hospitality | 2025 |
| Jiyong Ltd | Hospitality | 2024 |