| IAN Costello Ltd | Construction | 2013 |
| IAN Gicquel Limited | Other services | 2022 |
| ICD (NE) Ltd | Administrative & support | 2021 |
| ICP UK Group Ltd | Financial services | 2026 |
| ICT Imports Limited | Wholesale & retail | 2023 |
| ID Joinery Limited | Construction | 2023 |
| Identity Consult Group Limited | Financial services | 2017 |
| Identity Investments Limited | Professional & scientific | 2015 |
| IHO Coatings Ltd | Construction | 2019 |
| Imagidor Studios CIC | Education | 2025 |
| Impressed Wholesale Ltd | Wholesale & retail | 2019 |
| IN Automotives Ltd | Wholesale & retail | 2025 |
| IN Black Engulfing Ltd | Information & communication | 2024 |
| IN Person Connections Ltd | Administrative & support | 2025 |
| IN the Detail Copywriting Limited | Administrative & support | 2022 |
| Incentive Financial Ltd | Financial services | 2013 |
| Indicare Limited | Health & social care | 2023 |
| Indie Consultants Limited | Professional & scientific | 2024 |
| Industrial Access Group Ltd | Manufacturing | 2025 |
| Infinity Stoves and Fires Ltd | Wholesale & retail | 2019 |
| Infinity Stoves Ltd | Wholesale & retail | 2016 |
| Inka Solutions Limited | Professional & scientific | 2014 |
| Inprimature Limited | Information & communication | 2016 |
| Insideinsights Ltd | Information & communication | 2025 |
| Inspectic Ltd | Professional & scientific | 2023 |
| Instanceone Ltd | Information & communication | 2009 |
| Instinctive Flooring Limited | Construction | 2016 |
| Insulation & Buoyancy Services Limited | Extraterritorial | 2008 |
| Interiors With ALF Limited | Professional & scientific | 2021 |
| International Soccer League Pathway Ltd | Arts & recreation | 2026 |
| Invetel Limited | Wholesale & retail | 2001 |
| Ions Talent Partners Limited | Administrative & support | 2018 |
| Ipcom United Kingdom Limited | Financial services | 2024 |
| IRB Developments Limited | Construction | 2003 |
| Iron Hand Tattooing Ltd | Other services | 2019 |
| Isdoel Limited | Professional & scientific | 2014 |
| Isopartner UK Limited | Manufacturing | 1989 |
| Italian Leisure Limited | Hospitality | 2018 |
| Ivanhoe Forge Limited | Manufacturing | 1971 |
| Ivital Health Ltd | Health & social care | 2025 |
| Ivybay Ltd | Hospitality | 2025 |
| J & AV Project Services Limited | Administrative & support | 2016 |
| J & R Properties (North East) Limited | Real estate | 2015 |
| J B Electrical Contractors (NE) Limited | Construction | 2020 |
| J H Harrison Investments Ltd | Real estate | 2010 |
| J M Property Refurbishments Limited | Construction | 2013 |
| J R Electrical Contractors Limited | Construction | 2020 |
| J R Fisheries Limited | Wholesale & retail | 2013 |
| J Ridley Electrical Ltd | Construction | 2022 |
| J W Jefferson & Co Limited | Professional & scientific | 2021 |
| J. M. Brickwork Solutions Limited | Construction | 2018 |
| J. Richardson Management and Design Services Limited | Construction | 1975 |
| J.B (North East) Ltd | Hospitality | 2015 |
| J.J. Gilhespie Limited | Transport & logistics | 1987 |
| J.R.Campey & Sons Limited | Construction | 2013 |
| JA Gould Inspection Ltd | Other services | 2014 |
| Jackanackanory Ltd | Arts & recreation | 2023 |
| Jackdan Design Limited | Professional & scientific | 2010 |
| Jackson Steel Ltd | Construction | 2025 |
| Jacqui Martin Design Limited | Professional & scientific | 2023 |
| JAK & the Bean Ltd | Hospitality | 2023 |
| Jakd Holdings Ltd | Financial services | 2024 |
| JAM JAR Cinema Bar and Events Limited | Information & communication | 2017 |
| JAM JAR Cinema C.I.C. | Information & communication | 2012 |
| Jamelia Group Ltd | Wholesale & retail | 2016 |
| Jameniola Ltd | Mining & quarrying | 2024 |
| James Macleod Consulting Limited | Information & communication | 2021 |
| Jamie Carrahar Limited | Professional & scientific | 2007 |
| Jamieson School of Music Ltd | Education | 2024 |
| Jamiesons Properties Ltd | Real estate | 2026 |
| Jammy Agency Ltd. | Manufacturing | 2020 |
| Jamus (NE) Ltd | Arts & recreation | 2025 |
| Japrop (NE) Ltd | Real estate | 2025 |
| JAS Automotive Ltd | Wholesale & retail | 2024 |
| Jason Campbell Builders Limited | Construction | 2016 |
| Jason Cheng Limited | Hospitality | 2013 |
| Javel Groupe Limited | Other services | 2022 |
| Jay.K Ltd | Information & communication | 2026 |
| JB & JB Properties Limited | Households | 2025 |
| JB 81 Ltd | Health & social care | 2025 |
| JBR Offshore Solutions Limited | Manufacturing | 2015 |
| Jbyte Software Ltd | Information & communication | 2025 |
| JC Offshore Engineering Ltd | Other services | 2016 |
| JCG Heating & Plumbing Services Ltd | Other services | 2014 |
| JD Access Solutions Ltd | Construction | 2019 |
| JD Commercial Consulting Limited | Wholesale & retail | 2023 |
| JD Properties North East Limited | Real estate | 2025 |
| JD Renewable Services Ltd | Professional & scientific | 2026 |
| JDR Ventilation Limited | Other services | 2025 |
| Jefco Developments Ltd | Professional & scientific | 2022 |
| Jefco Limited | Real estate | 2018 |
| JEM Career Coaching Limited | Professional & scientific | 2024 |
| Jenkinson & Burridge Property Ltd | Real estate | 2023 |
| Jenkinsons Glaziers & Upvc Limited | Construction | 2015 |
| Jericho Finance Ltd | Financial services | 2018 |
| Jess & James Travel Ltd | Administrative & support | 2024 |
| JG WTG Services Ltd | Manufacturing | 2024 |
| JGB Offshore Limited | Construction | 2014 |
| JGF Accountancy Services Limited | Professional & scientific | 1998 |
| JGS Consulting Ltd | Professional & scientific | 2010 |