| Jack's Katch Ltd | Wholesale & retail | 2002 |
| Jack's Katch of Grimsby Limited | Wholesale & retail | 2019 |
| Jackcarsen Limited | Construction | 2024 |
| Jackieboi Ltd | Information & communication | 2022 |
| Jackson Partners Ltd | Professional & scientific | 2006 |
| Jackson Transport Ltd | Transport & logistics | 2019 |
| Jackson, Green and Preston Auctioneers Limited | Wholesale & retail | 2024 |
| Jackson, Green and Preston Estate Agents and Property Management Limited | Real estate | 2024 |
| Jackson, Green and Preston Surveyors Limited | Professional & scientific | 2024 |
| Jackstone Food Systems Ltd | Extraterritorial | 2006 |
| Jackstone Freezing Systems Ltd | Manufacturing | 2003 |
| Jade Clay Hair & Make UP Artist Ltd | Other services | 2021 |
| Jafeica Limited | Extraterritorial | 2015 |
| Jafeica Terrace Ltd | Extraterritorial | 2015 |
| JAG Systems Limited | Professional & scientific | 2008 |
| Jagadish Properties Limited | Real estate | 2016 |
| Jaines & SON (Grimsby) Limited | Wholesale & retail | 1947 |
| Jaines Roofing Limited | Construction | 2019 |
| Jaines White Associates Limited | Professional & scientific | 2013 |
| Jakd Properties Limited | Real estate | 2021 |
| Jakeira Property Ltd | Real estate | 2020 |
| Jakeman Scott Lettings Ltd | Real estate | 2026 |
| Jakeman Scott Property Ltd | Construction | 2013 |
| Jama Services Limited | Transport & logistics | 2018 |
| James Allen Classic & Vintage Limited | Wholesale & retail | 2002 |
| James Bird Decorating Services Ltd | Construction | 2019 |
| James Cane Estate Agent Ltd | Real estate | 2024 |
| James Foster & Co Building Services Limited | Construction | 2020 |
| James Gibbons Plumbing & Heating Limited | Construction | 2019 |
| James Gibson (Lincolnshire) Limited | Other services | 2010 |
| James Gray Home Improvements Limited | Construction | 2005 |
| James Waumsley Building Limited | Construction | 2026 |
| James Williams Photography Limited | Professional & scientific | 2024 |
| James Williams Properties Limited | Real estate | 2026 |
| Jamie Worrall Ltd | Construction | 2016 |
| JAMIMECAKEB4 Ltd | Wholesale & retail | 2025 |
| Jamol Limited | Professional & scientific | 2003 |
| Janefrany Limited | Health & social care | 2022 |
| Janice at 47 Limited | Other services | 2017 |
| Janus Hestia Limited | Construction | 2023 |
| Jaroslaw Pruchenski Driver Van Limited | Transport & logistics | 2021 |
| Jarrizon Ventures Ltd | Wholesale & retail | 2025 |
| JAS Developers U.K. Limited | Construction | 2017 |
| JAS Road Freight (UK) Limited | Transport & logistics | 1980 |
| Jason Rocks Funeral Services Limited | Other services | 2020 |
| Jason's Fresh Grimsby Fish Limited | Wholesale & retail | 2020 |
| Jatl Ltd | Construction | 2024 |
| JAW Media Productions Limited | Information & communication | 2019 |
| Jawor Transport Ltd | Transport & logistics | 2024 |
| JAY Grimsby Limited | Other services | 2023 |
| Jayquor Limited | Other services | 2020 |
| Jaysyl Limited | Information & communication | 2014 |
| Jaywick Stores Ltd | Wholesale & retail | 2017 |
| Jazz Clothing Limited | Wholesale & retail | 2002 |
| JB Mortgage Solutions Ltd. | Financial services | 2018 |
| Jbarratt Rope Access Services Ltd | Construction | 2025 |
| Jbis Properties Ltd | Real estate | 2024 |
| Jbkyr Ltd | Health & social care | 2025 |
| JBN Medical Ltd | Health & social care | 2023 |
| JBR Property Solutions Limited | Real estate | 2023 |
| Jburton Site Services Ltd | Professional & scientific | 2025 |
| JC Automotive Group Ltd | Wholesale & retail | 2017 |
| JC Technical Solutions Ltd | Professional & scientific | 2026 |
| JCA Group Services Ltd | Professional & scientific | 2026 |
| Jcbg Limited | Health & social care | 2018 |
| JCG Ultrasound Limited | Health & social care | 2026 |
| JCI Blue Sky Ltd | Professional & scientific | 2026 |
| JCI Engineering & Consultancy Ltd | Health & social care | 2012 |
| Jciec Group Limited | Real estate | 2021 |
| JCS Holdings (Grimsby) Limited | Hospitality | 2022 |
| JD OPS Consultancy Limited | Professional & scientific | 2025 |
| JD Print Ltd | Manufacturing | 2015 |
| JDM Turbine Limited | Professional & scientific | 2016 |
| Jdqs Ltd | Information & communication | 2017 |
| JE Artistics Ltd | Arts & recreation | 2024 |
| Jeff Gates Joinery & Building Limited | Construction | 2003 |
| Jelley Fish Ltd | Wholesale & retail | 2014 |
| Jelonek Ltd | Transport & logistics | 2025 |
| Jemm Services Limited | Agriculture & fishing | 2023 |
| Jemsel Export Ltd | Transport & logistics | 2009 |
| Jencare Limited | Other services | 2000 |
| Jeneva Developments Ltd | Construction | 2019 |
| Jenoli Limited | Construction | 2017 |
| Jenpark Limited | Real estate | 2006 |
| Jentech Engineering Group Limited | Professional & scientific | 2026 |
| Jentech Engineering Limited | Professional & scientific | 2021 |
| Jepa Holdings Ltd | Construction | 2022 |
| Jeremy Bodian Surgical Service Ltd | Professional & scientific | 2021 |
| Jerome Eliane Partnership Ltd | Professional & scientific | 2025 |
| JES Billingborough Limited | Wholesale & retail | 2025 |
| Jessy Care Ltd | Health & social care | 2020 |
| Jet-Tech Limited | Water & waste | 2002 |
| Jettaway Cleaning Services Limited | Administrative & support | 2021 |
| JF Classic Cars & Bikes Limited | Wholesale & retail | 2025 |
| JFP Aero Ltd | Professional & scientific | 2017 |
| JG Driveways Ltd | Administrative & support | 2023 |
| Jgbx Limited | Health & social care | 2018 |
| JGN Engineering Limited | Construction | 2017 |
| JGP Company Holdings Limited | Administrative & support | 2024 |
| JGP Property Maintenance Limited | Construction | 2024 |