| Hello Cornwall Limited | Wholesale & retail | 2020 |
| Hendra Meadows Management Company Ltd | Households | 2021 |
| Heritage Energy and Building Services Consultancy Ltd | Professional & scientific | 2016 |
| Hewas Inn PUB Company Ltd | Hospitality | 2021 |
| Hewas Water Self Storage Limited | Transport & logistics | 2025 |
| Hewaswater Engineering Ltd | Manufacturing | 1985 |
| Hewaswater Holdings Limited | Professional & scientific | 2010 |
| Hewaswater Scaffolding Limited | Construction | 2004 |
| HEX Consultants Ltd | Administrative & support | 2023 |
| HI Yield Ltd | Information & communication | 2018 |
| HI Yield Products Limited | Information & communication | 2021 |
| HI Yield Trustee Ltd | Professional & scientific | 2025 |
| Hideaway Cottage Ltd | Real estate | 2020 |
| Higher Brynn Farm Limited | Agriculture & fishing | 2022 |
| Higher Pentreath Campsite Ltd | Hospitality | 2017 |
| Hillember Limited | | 1975 |
| HIP Nautic Ltd | Hospitality | 2020 |
| HJR Carpentry Ltd | Construction | 2018 |
| Holiday Lets Cornwall Ltd | Hospitality | 2019 |
| Home NOT Hospital Ltd | Health & social care | 2021 |
| Hooked on Cornwall Limited | Wholesale & retail | 2025 |
| Hope and Anchor Inns Ltd | Hospitality | 2021 |
| Hope Housing (Cornwall) Ltd | Hospitality | 2022 |
| Hore Developments Ltd | Construction | 2024 |
| Hosken Holdings Ltd | Financial services | 2025 |
| Hotshots Limited | Extraterritorial | 2014 |
| House to Home Logistics Ltd | Transport & logistics | 2025 |
| HOUSES2HOUSE Ltd | Transport & logistics | 2024 |
| HPS Cornwall Limited | Professional & scientific | 2021 |
| HR David & Company Ltd | Professional & scientific | 2014 |
| HR Vitals Ltd | Professional & scientific | 2021 |
| Hsjd Ltd | Health & social care | 2021 |
| HTT3 Solutions Ltd | Administrative & support | 2026 |
| Hurley Books Limited | Wholesale & retail | 2014 |
| HUT & Hound Limited | Hospitality | 2011 |
| IAN Studley Carpentry & Construction Limited | Construction | 2023 |
| Ibis Construction Ltd | Construction | 2001 |
| Ifeoma Limited | Wholesale & retail | 2025 |
| Iliad Development Ltd | Real estate | 2019 |
| Imaginal Collective Limited | Education | 2019 |
| IML Labels & Systems Limited | Manufacturing | 1997 |
| Immersive Travel Asia Limited | Administrative & support | 2026 |
| Impecunious Limited | Financial services | 2017 |
| IN Caring Hands Limited | Education | 2015 |
| Inductive Power Projection Ltd | Professional & scientific | 2020 |
| Infinitech IT Ltd | Information & communication | 2025 |
| Info Italiano Ltd. | Information & communication | 2017 |
| Ingaf Ltd | Information & communication | 2016 |
| Inin Property Investments Ltd | Real estate | 2025 |
| Initié Ltd | Arts & recreation | 2016 |
| Innovail Ltd | Professional & scientific | 2025 |
| Inox (Cornwall) Limited | Real estate | 2014 |
| Insoll Interiors Ltd | Manufacturing | 2018 |
| Inspire NLP Limited | Education | 2016 |
| Instructuk Resources Ltd | Professional & scientific | 2011 |
| Integritas Associates Ltd | Other services | 2014 |
| Ismeer House Management Company Limited | Households | 2019 |
| Iver Limited | Hospitality | 2003 |
| IVY Prideaux Ltd | Wholesale & retail | 2024 |
| IVY Rose Publishing Ltd | Information & communication | 2021 |
| J & H Developments (S.W) Ltd | Construction | 2025 |
| J D Decorating S.W Ltd | Construction | 2025 |
| J H Reeves Builders Limited | Construction | 2007 |
| J H Watson Engineering Services Limited | Manufacturing | 2013 |
| J J Conibear Ltd | Professional & scientific | 2024 |
| J L Oliver Ltd | Transport & logistics | 2023 |
| J R Lewis Property Management Ltd | Real estate | 2021 |
| J S Martin Plumbing & Heating Ltd | Construction | 2023 |
| J Truscott Property and Garden Services Ltd | Construction | 2022 |
| J&H Livery Ltd | Agriculture & fishing | 2026 |
| J&M Futures Ltd | Real estate | 2017 |
| J. Erasmus Installations Ltd | Construction | 2018 |
| Jack Lewis Fabrications Limited | Manufacturing | 2017 |
| Jacobs Roofing Limited | Construction | 2018 |
| Jade Garden Takeaway Ltd | Hospitality | 2017 |
| James Cormack Limited | Administrative & support | 2022 |
| Jass South West Limited | Real estate | 2023 |
| JBQ Surveying Ltd | Professional & scientific | 2024 |
| JD Homes (SW) Ltd | Construction | 2023 |
| JD Live Productions Ltd | Arts & recreation | 2018 |
| Jdel Building Ltd | Construction | 2025 |
| Jhamka Limited | Wholesale & retail | 2025 |
| JIM Holt Limited | Professional & scientific | 2017 |
| JJL Contracting Ltd | Information & communication | 2013 |
| JLN Driving School Limited | Education | 2024 |
| JM Haulage & Drivers Limited | Transport & logistics | 2025 |
| Jmott International Limited | Wholesale & retail | 2025 |
| JNB Developments SW Ltd | Construction | 2025 |
| John Hersey Studio Ltd | Professional & scientific | 2025 |
| John Hunkin Limited | Agriculture & fishing | 2014 |
| Johncharlessw Limited | Construction | 2026 |
| Joli Coding Services Ltd | Administrative & support | 2025 |
| Jones Mobility Ltd | Wholesale & retail | 2026 |
| Josh Dunn Construction & Landscaping Ltd | Construction | 2025 |
| Jovern Marine Limited | Agriculture & fishing | 2013 |
| JP Extensions & Renovations Ltd | Construction | 2013 |
| Jp(Sw) Ltd | Real estate | 2017 |
| Jparan Properties Ltd | Real estate | 2025 |
| Jparan Stores Ltd | Wholesale & retail | 2025 |
| JR Southwest Scaffolding Ltd | Construction | 2021 |