| Imaginative Productions Limited | Manufacturing | 2011 |
| Imagnative Productions Hospitality Ltd | Hospitality | 2025 |
| IML Design Limited | Professional & scientific | 2025 |
| Impact Organics Ltd | Wholesale & retail | 2022 |
| Impact Qhse Limited | Public administration | 2024 |
| Impact TA Limited | Professional & scientific | 2025 |
| IN Harmony Food Revolution CIC | Hospitality | 2016 |
| IN OFF the Clock Limited | Hospitality | 2024 |
| Independent Employment Limited | Professional & scientific | 2019 |
| Independent Insulation Services Limited | Construction | 2023 |
| Industrial Thinking Limited | Information & communication | 2007 |
| Ingenuit Limited | Information & communication | 2017 |
| Ingleby Court Residents' Association Limited | Households | 1984 |
| Ings Accountancy Limited | Professional & scientific | 2019 |
| Injector Removal Limited | Wholesale & retail | 2011 |
| Inkx Apparel Limited | Wholesale & retail | 2026 |
| Inscout Network Ltd | Administrative & support | 2024 |
| Inspec Qa/Qc Ltd | Professional & scientific | 2016 |
| Integrated Safety Solutions Limited | Mining & quarrying | 2014 |
| Intellisight Optics Ltd | Wholesale & retail | 2023 |
| International Absorbents Ltd | Professional & scientific | 2006 |
| Internet Labels Limited | Professional & scientific | 2001 |
| Invested Education Ltd | Education | 2021 |
| IOI Properties Limited | Real estate | 2022 |
| Irolyat Ltd | Professional & scientific | 2013 |
| Ironopolis Consult Limited | Professional & scientific | 2022 |
| Isai Ltd | Hospitality | 2019 |
| Isotank (2006) Limited | Real estate | 2006 |
| Isotank (2010) Limited | Real estate | 2010 |
| Isotank Depot Services Limited | Administrative & support | 2003 |
| Isotank Services Limited | Transport & logistics | 1979 |
| Isotank Transport Services Limited | Transport & logistics | 2003 |
| Istanbul Barber Redcar Ltd | Other services | 2024 |
| Istanbul Shawarma 4U Ltd | Hospitality | 2020 |
| IVI SEO Ltd | Professional & scientific | 2022 |
| J & T Water Consultants Ltd | Manufacturing | 2014 |
| J Allan Electrical Services Limited | Construction | 2010 |
| J Allan Investments Limited | Real estate | 2024 |
| J Best Carpets Ltd | Wholesale & retail | 2025 |
| J C Sykes Ltd | Construction | 2025 |
| J Hubbard Limited | Construction | 2015 |
| J K Macdonald Ltd | Health & social care | 2025 |
| J Ross Offshore Ltd | Professional & scientific | 2026 |
| J Scrafton Ltd | Construction | 2023 |
| J&A Electrical Limited | Construction | 2019 |
| J&M Electrics Ltd | Professional & scientific | 2026 |
| J&T Tyres Ltd | Wholesale & retail | 2023 |
| J&W Driveways Ltd | Construction | 2021 |
| J-Bow Construction Limited | Construction | 2025 |
| J.R Construction (N.E) Ltd | Construction | 2017 |
| J.R Plant Hire (N.E) Ltd | Administrative & support | 2017 |
| J4 Partnership LLP | | 2019 |
| Jaba Lettings Ltd | Real estate | 2024 |
| Jackintheboxtherapy Ltd | Health & social care | 2023 |
| Jake Macgregor Consulting Ltd | Professional & scientific | 2026 |
| James Cook DJ Limited | Other services | 2014 |
| Jamie Grey Limited | Information & communication | 2021 |
| Japeva Limited | Real estate | 2021 |
| Jarred Thomas Inspection Limited | Professional & scientific | 2019 |
| JAZ Event Management Ltd | Administrative & support | 2023 |
| JB Discounted Beds & Furniture Limited | Wholesale & retail | 2016 |
| JB Property Developments North East Ltd | Real estate | 2025 |
| JBT Construction Ltd | Construction | 2025 |
| Jccswelding Ltd | Mining & quarrying | 2016 |
| JCM Offshore Consultants Ltd | Professional & scientific | 2016 |
| JCM Studios Limited | Information & communication | 2026 |
| JD Building Services Limited | Construction | 2025 |
| Jett Consultancy Limited | Professional & scientific | 2021 |
| Jeyos Limited | Energy | 2019 |
| Jimbo N Robbo Limited | Professional & scientific | 2026 |
| JJ Delivery Ltd | Transport & logistics | 2026 |
| JJ Scaffolding (NE) Ltd | Construction | 2025 |
| JJA Electrical Ltd | Construction | 2024 |
| Jjgannon Limited | Manufacturing | 2025 |
| JKG Consulting Ltd | Professional & scientific | 2023 |
| JL Safety Solutions Ltd | Construction | 2022 |
| Jmns Holdings Ltd | Real estate | 2022 |
| JOC Access Ltd | Administrative & support | 2022 |
| Joelyco Limited | Hospitality | 2025 |
| John Henson Car Parks Limited | Transport & logistics | 2011 |
| John Poole Transport Limited | Transport & logistics | 2015 |
| Johnson Letting & Property Ltd | Real estate | 2026 |
| Johnsons & Co Accountants Ltd | Professional & scientific | 2014 |
| Johnsons & Co Ltd | Professional & scientific | 2011 |
| Johnsons Access Limited | Construction | 2015 |
| Jola Pizzeria Ltd | Hospitality | 2025 |
| Jolly Good Wedding Films Ltd | Information & communication | 2025 |
| Jonathan Cooper Fibre Ltd | Information & communication | 2025 |
| Josh Boyce Ltd | Professional & scientific | 2019 |
| Jowers Properties Ltd | Real estate | 2024 |
| JPK E & I Engineering Solutions Limited | Professional & scientific | 2017 |
| JPK Property Holdings Limited | Hospitality | 2019 |
| JRR Electrical Resourcing Limited | Manufacturing | 2016 |
| JS Offshore Solutions Ltd | Construction | 2026 |
| JTP Electrical Limited | Construction | 2014 |
| JTS Marine Services Limited | Administrative & support | 2012 |
| Jude Smith Ltd | Construction | 2017 |
| Just Enhance Limited | Health & social care | 2017 |
| Just Hair [Redcar] Limited | Other services | 2010 |
| Just Weight Management Ltd | Health & social care | 2021 |