| Hypnotherapy Newcastle Ltd | Health & social care | 2022 |
| I&I Beauty Salon Ltd | Other services | 2021 |
| I.P. Railtech Services Ltd | Manufacturing | 2021 |
| IAN Groom Consultancy Limited | Professional & scientific | 2023 |
| IAN Lambert Ltd | Construction | 2024 |
| IAN Mason Design Services Limited | Professional & scientific | 2011 |
| Icomss Ltd | Information & communication | 2015 |
| Iconic Cyber Protection CIC | Information & communication | 2026 |
| ICT North Ltd | Information & communication | 2015 |
| Icut.Hair Limited | Other services | 2018 |
| IDEAS4IT Ltd | Information & communication | 2023 |
| Imexe Limited | Wholesale & retail | 2025 |
| Incline Investments Limited | Real estate | 2022 |
| Independent Scaffold Limited | Extraterritorial | 2008 |
| India Echo Ltd | Real estate | 2024 |
| Indigo Multimedia Limited | Manufacturing | 1995 |
| Indigo Scot Construction North East Ltd | Construction | 2025 |
| Industrial Abseiling Services Ltd | Mining & quarrying | 2025 |
| Infinity Fitness North East Ltd | Arts & recreation | 2018 |
| Information Consulting Business Services Ltd | Information & communication | 2017 |
| Inspired Souls Ltd | Education | 2021 |
| INT Struct Ltd | Construction | 2009 |
| Integra Labs Ltd | Information & communication | 2026 |
| Interglaze Glass Solutions Ltd | Construction | 2014 |
| International Syalons (Newcastle) Limited | Manufacturing | 1994 |
| Irthing Limited | Professional & scientific | 2021 |
| IT Repair MAN Limited | Other services | 2016 |
| IT Solutions North Ltd | Information & communication | 2012 |
| Italian Grub NE Ltd | Hospitality | 2026 |
| Izzy Hotel Ltd | Hospitality | 2025 |
| J & C Facilities Ltd | Administrative & support | 2024 |
| J & J (NE) Ltd | Hospitality | 2017 |
| J & P Car Sales Ltd | Wholesale & retail | 2017 |
| J & W Groundwork & Brickwork Ltd | Construction | 2023 |
| J and J Cafe Ltd | Hospitality | 2015 |
| J Brownlee Roofing Ltd | Construction | 2021 |
| J D Leathard Electrical Ltd | Construction | 2026 |
| J H Johnson Shopfitters Limited | Construction | 2010 |
| J K Roofing Specialist Ltd | Construction | 2015 |
| J&D Lettings NE Limited | Real estate | 2023 |
| J&S Limited | Professional & scientific | 2017 |
| J. Mccheyne and Sons Limited | Real estate | 1984 |
| J.L.P Developments Ltd | Real estate | 2017 |
| J.O. Property Development Limited | Real estate | 2021 |
| Jackson James Limited | Administrative & support | 2022 |
| JAD Welding Services Ltd | Wholesale & retail | 2025 |
| Jalo Planning Ltd | Professional & scientific | 2011 |
| James Recovery Limited | Other services | 2018 |
| James' Lifting Services Ltd | Manufacturing | 2014 |
| JAN Cheese Ltd | Manufacturing | 2023 |
| Jane Haswell Ltd | Professional & scientific | 2025 |
| Jays Courier (NE) Ltd | Transport & logistics | 2020 |
| Jaytek Coatings Ltd | Manufacturing | 2024 |
| JB Drone OPS Ltd | Professional & scientific | 2026 |
| JB Joinery & Interiors Ltd | Construction | 2021 |
| JBD Engineering Services Ltd | Other services | 2018 |
| JBM Commercial Limited | Extraterritorial | 2024 |
| JD Rewinds Ltd | Manufacturing | 2018 |
| Jefes Grill Limited | Hospitality | 2026 |
| Jefesgrill One Ltd | Hospitality | 2024 |
| Jefesgrill Two Ltd | Hospitality | 2024 |
| Jesmond Urban Aspirations Limited | Real estate | 2010 |
| Jfac Electricals Ltd | Wholesale & retail | 2026 |
| JFY Catering Ltd | Hospitality | 2026 |
| Jhar Properties Ltd | Real estate | 2024 |
| Jhoko Ltd | Manufacturing | 2024 |
| Jimmy Mcintyre Software and Development Ltd | Information & communication | 2016 |
| JJI Solutions Ltd | Information & communication | 2025 |
| Jjlc Consultancy Ltd | Professional & scientific | 2023 |
| JJM Leisure Ltd | Hospitality | 2021 |
| Jlanka Gems Ltd | Wholesale & retail | 2025 |
| JMS Stewart Ltd | Construction | 2024 |
| JMW Lifting Limited | Construction | 2024 |
| JO Jo's Holiday Lettings Ltd | Real estate | 2016 |
| JO Jo's Property Agents Ltd | Real estate | 2014 |
| Joga Health Community Interest Company | Health & social care | 2024 |
| John N Dunn (Newcastle) Limited | Construction | 2010 |
| John N Dunn Group Limited | Construction | 2007 |
| John N Dunn Holdings Limited | Financial services | 2016 |
| John N Dunn Limited | Construction | 2016 |
| Johnson Decorators Ltd | Construction | 2022 |
| Johnson Properties Investments Limited | Financial services | 2023 |
| Johnston's Wind Technologies Ltd | Manufacturing | 2022 |
| Joseph's Letting Services Ltd | Real estate | 2025 |
| Joseph's Property Services Ltd | Construction | 2025 |
| Journey With Stars Ltd | Education | 2022 |
| JPD Holdings NE Ltd | Hospitality | 2025 |
| JPM Auto Bodies Limited | Wholesale & retail | 2012 |
| JRG Civils Limited | Construction | 2019 |
| JSJ Renovations Limited | Construction | 2021 |
| JT Precious Metals Limited | Wholesale & retail | 2021 |
| JT Roofing North East Limited | Construction | 2019 |
| JTH Services(North East) Ltd | Construction | 2024 |
| JTO Roofing and Cladding Ltd | Construction | 2022 |
| JTR Ventures Ltd | Manufacturing | 2025 |
| JTW Inspections Ltd | Mining & quarrying | 2023 |
| Just Enjoy Ltd | Hospitality | 2018 |
| Juvam Energies Ltd | Professional & scientific | 2024 |
| K Glen Ltd | Other services | 2017 |
| K L B PMC Ltd | Construction | 2019 |