| Good Taste PR Limited | Information & communication | 2019 |
| Gordon Lamb Properties Limited | Real estate | 2017 |
| Green Sunrise Solutions Limited | Construction | 2025 |
| Ground Water Consult Ltd | Professional & scientific | 2022 |
| Grwth C&C Ltd | Other services | 2023 |
| Gsi:Ne Ltd | Construction | 2009 |
| GWR UPS Services Ltd | Information & communication | 2016 |
| H and O Assets Ltd | Real estate | 2021 |
| H M Vehicle Transportation Limited | Transport & logistics | 2022 |
| H.E.S Halls Electrical Services Ltd | Construction | 2004 |
| Hair & Beauty Seaham Ltd | Other services | 2025 |
| Hairdressing @ NO4 Limited | Other services | 2013 |
| Haley Real Estates Limited | Real estate | 2025 |
| Halo's Luxury Homes & Architecture Vision Ltd | Construction | 2025 |
| Happie Mappie Ltd | Information & communication | 2024 |
| Happy & Marti Ltd | Wholesale & retail | 2024 |
| Harbour Electrical Services Limited | Manufacturing | 2023 |
| Harbour Tandoori Limited | Hospitality | 2018 |
| Harbour View Leisure Ltd | Hospitality | 2026 |
| Harbour Wave Inspection Ltd | Professional & scientific | 2022 |
| Harbourtandooriseaham Ltd | Hospitality | 2024 |
| Hardy Properties Investment Limited | Real estate | 2016 |
| Hare Contracts Ltd | Water & waste | 2021 |
| Harleyquin Limited | Hospitality | 2019 |
| Harri&Co Ltd | Wholesale & retail | 2026 |
| Hartox Limited | Professional & scientific | 1995 |
| Hawthorn Developments (North East) Limited | Real estate | 2003 |
| Hawthorn Hospitality Ltd | Hospitality | 2017 |
| Haydon Homes Limited | Construction | 2006 |
| Haylo Ltd | Other services | 2026 |
| HC Realty & Logistics Ltd | Real estate | 2024 |
| HCA Properties Limited | Construction | 2014 |
| Headway Point Limited | Water & waste | 2012 |
| Hearth & Husk Ltd | Manufacturing | 2026 |
| Hearth to Hearth Ltd | Wholesale & retail | 2013 |
| Hegartys Estate Agents Ltd | Real estate | 2012 |
| Helen Hogan Safeguarding Matters Limited | Education | 2025 |
| Helix Forensic Science Ltd | Professional & scientific | 2020 |
| Help From Above Limited | Health & social care | 2024 |
| Hesledon Developments Ltd | Real estate | 2013 |
| Heywood Developments Ltd | Financial services | 2015 |
| High Fallowfield Land & Property Ltd | Construction | 2025 |
| High Tide Fitness Ltd | Other services | 2018 |
| HMS - Hydraulic & Mechanical Solutions Ltd | Manufacturing | 2025 |
| Holbrook Estate Agents Bishop Auckland Limited | Real estate | 2008 |
| Holbrook Estate Agents Hartlepool Limited | Real estate | 2015 |
| Holbrook Estate Agents Seaham Limited | Real estate | 1999 |
| Home and Building Solutions Ltd | Administrative & support | 2016 |
| Homefair (Holdings) Limited | Professional & scientific | 2008 |
| Homefair (North West) Limited | Wholesale & retail | 1998 |
| Homefair Blinds (U.K.) Limited | Manufacturing | 1986 |
| Homefair Blinds and Shutters Limited | Manufacturing | 2019 |
| Hong Kong Rose (Seaham) Ltd | Hospitality | 2025 |
| House of Mooshki Ltd | Manufacturing | 2009 |
| Housewarmers Contracts Limited | Construction | 2014 |
| Humbles Bistro Ltd | Hospitality | 2017 |
| Hunter Trading Group Ltd | Wholesale & retail | 2023 |
| I.G.C Properties Limited | Real estate | 2014 |
| IG Motors Ltd | Wholesale & retail | 2019 |
| Include 'in' Autism Community Interest Company | Health & social care | 2017 |
| Include Elite Workforce Ltd | Administrative & support | 2026 |
| Include in Autism NE Ltd | Public administration | 2025 |
| Industrial Deep Cleaning Limited | Administrative & support | 2003 |
| Innoplace Ltd | Professional & scientific | 2026 |
| Inside OUT Hair, Beauty and Wellness Ltd | Health & social care | 2025 |
| Inside OUT Yoga Wellness Community Interest Company | Health & social care | 2023 |
| Inspection PMC Limited | Other services | 2015 |
| Instatan Murton Limited | Other services | 2023 |
| Integrated Processing Technologies Limited | Administrative & support | 2015 |
| Intelec Electrical Solutions Ltd | Construction | 2024 |
| International Cookware Limited | Transport & logistics | 2005 |
| Iron Gang Ltd | Arts & recreation | 2024 |
| ITC Electrical Services Limited | Construction | 2019 |
| ITC Plumbing and Heating Services Limited | Construction | 2003 |
| Itgill Consulting Services Limited | Information & communication | 2010 |
| J ST Louis Limited | Wholesale & retail | 2011 |
| J. Taylor Drilling Services Limited | Construction | 2023 |
| J.G. Hare (Farming) Limited | Agriculture & fishing | 2016 |
| J.Mcmeekin Ltd | Manufacturing | 2023 |
| J.T.C. Reinforcements (North East) Limited | Construction | 2021 |
| Jack Roberts Marketing Limited | Professional & scientific | 2025 |
| Jacksnack Ltd | Hospitality | 2026 |
| James Winn Limited | Real estate | 2005 |
| Jamie Collings Joinery Ltd | Manufacturing | 2023 |
| Jasflo's Finds Ltd | Wholesale & retail | 2024 |
| JAY Whittaker Photography Ltd | Professional & scientific | 2025 |
| JBN Psychometrics Consultant Ltd | Professional & scientific | 2026 |
| Jd's Sports Bar Ltd | Hospitality | 2025 |
| Jd's Sports Bar NE Limited | Hospitality | 2026 |
| JEA Inspection Services Ltd | Professional & scientific | 2020 |
| Jeff Houston Optometrist Limited | Health & social care | 2012 |
| Jennings Techchem Ltd | Professional & scientific | 2020 |
| Jianu Group Ltd | Information & communication | 2026 |
| Jill Moore Sales and Lettings Limited | Real estate | 2008 |
| JL Properties NE Ltd | Real estate | 2024 |
| JLH Developments Limited | Construction | 2008 |
| John Ridley GAS and Plumbing Services Limited | Other services | 2014 |
| Jones Consulting Services Limited | Construction | 2023 |
| Jones Property Solutions Ltd | Real estate | 2021 |
| JPM (NE) Ltd | Wholesale & retail | 2021 |