| Hopscotch Home Services Ltd | Households | 2011 |
| Horfield Dental Practice Limited | Health & social care | 2013 |
| Horizon IFP Ltd | Financial services | 2014 |
| Horizon Mortgage Solutions Ltd | Financial services | 2022 |
| Hosken Construction Ltd | Construction | 2026 |
| House Management Services Limited | Hospitality | 2009 |
| House of Damnation CIC | Arts & recreation | 2023 |
| Housework Cornwall Ltd | Administrative & support | 2025 |
| Howard & Jackson Construction Limited | Construction | 2013 |
| Howes Properties Limited | Administrative & support | 2017 |
| Howsonco Limited | Professional & scientific | 2023 |
| HOY (SW) Ltd | Professional & scientific | 2022 |
| HS Heys Scientific Limited | Manufacturing | 2025 |
| HSC Mobility Limited | Wholesale & retail | 2010 |
| Hsee Ltd | Information & communication | 2023 |
| HTS Church Limited | Hospitality | 2018 |
| Huckleberry Management Co Limited | Households | 2020 |
| Hume Associates Mortgage Services Limited | Financial services | 2016 |
| Hummingbird Construction Limited | Construction | 2025 |
| Hundred Percent Cornwall Ltd. | Hospitality | 2011 |
| Hunter Groundworks Ltd | Construction | 2021 |
| Hunter Imports Ltd | Wholesale & retail | 2024 |
| Hunter Survey Ltd | Professional & scientific | 2020 |
| Hustle & Roll Ltd | Wholesale & retail | 2023 |
| Hutch Agency Limited | Professional & scientific | 2017 |
| Hutch Holdings Limited | Real estate | 2016 |
| Hutchings Property Ltd | Real estate | 2025 |
| Hutchinson Limited | Information & communication | 2024 |
| Huus Design Limited | Manufacturing | 2025 |
| Hydroflux Corporation LP | | 2020 |
| Hydrogeology Consulting Limited | Professional & scientific | 2020 |
| Hypneuma Limited | Manufacturing | 2021 |
| I & M Fishing Ltd | Financial services | 2021 |
| I&M Stamford Properties Ltd | Real estate | 2018 |
| I-Eye Limited | Information & communication | 2009 |
| I4DETAIL Development Limited | Construction | 2012 |
| Iain Smith Surgery Ltd | Health & social care | 2019 |
| Iamyourcare Ltd | Health & social care | 2024 |
| IAN Hick Consulting Limited | Professional & scientific | 2022 |
| IBC Southwest Ltd | Construction | 2023 |
| ICF Cornwall Ltd | Construction | 2015 |
| Iconic Inc Limited | Other services | 2012 |
| IDA Tech LP | | 2021 |
| Igbo Ventures Ltd | Wholesale & retail | 2020 |
| Ignition Automotive Ltd | Financial services | 2008 |
| Ignition Credit PLC | Financial services | 2001 |
| IHP (Holsworthy) Limited | Real estate | 2001 |
| IKP Investments Limited | Real estate | 2022 |
| Ilexa Onboard Diagnostics Limited | Manufacturing | 2010 |
| Ilhs Corp Limited | Wholesale & retail | 2025 |
| Illustrated Living (ST Ives) Limited | Wholesale & retail | 2019 |
| Ilsc Education UK Limited | Financial services | 2025 |
| Imagine and Grow Ltd | Health & social care | 2020 |
| Imagine IF Partnership Ltd | Education | 2019 |
| Imaniglobal Group Ltd | Wholesale & retail | 2026 |
| IML Management Ltd | Construction | 2019 |
| Impacct Live Limited | Administrative & support | 2020 |
| Impact Cornwall CIC | Education | 2025 |
| Impact Fluid Solutions (UK) Limited | Professional & scientific | 2009 |
| Imperial Court and Regent House Residents Limited | Households | 2003 |
| Improot Limited | Information & communication | 2011 |
| Imtfa Events Ltd | Administrative & support | 2018 |
| IN 2 Services Ltd | Water & waste | 2020 |
| IN Touch Digital Limited | Information & communication | 2011 |
| IN-2 Housing Limited | Real estate | 2019 |
| IN2ENGINEERING Limited | Professional & scientific | 2018 |
| Inacoustic Limited | Professional & scientific | 2017 |
| Independent Air CON Limited | Construction | 2012 |
| Independent Motor Trade Factors Associated Limited | Wholesale & retail | 1978 |
| Indian Boutique Limited | Wholesale & retail | 2020 |
| Indie Records Ltd | Information & communication | 2016 |
| Industrial Electrical Repairs (Cornwall) Limited | Manufacturing | 2022 |
| Industrial Refrigeration Controls Limited | Professional & scientific | 2015 |
| Inet Digital (UK) Limited | Information & communication | 2011 |
| Influence Planning (Cornwall) Limited | Administrative & support | 2016 |
| Inforisk Limited | Administrative & support | 2018 |
| Infosynex Ltd | Extraterritorial | 2024 |
| Ingham SPV Ltd | Professional & scientific | 2025 |
| Inhouse Art Limited | Arts & recreation | 2022 |
| Inked Live UK Ltd | Professional & scientific | 2024 |
| Inkedfluence Ltd | Professional & scientific | 2025 |
| Inkfish Hair and Beauty Limited | Other services | 2014 |
| Innovation Factors Ltd | Professional & scientific | 2018 |
| Inspir EM Ltd | Professional & scientific | 2019 |
| Inspire Cornwall CIC | Education | 2010 |
| Inspire Cornwall Training Limited | Administrative & support | 2014 |
| Inspiredbywild Limited | Arts & recreation | 2019 |
| Inspiring Women Network CIC | Other services | 2012 |
| Installations Classic Kitchens Cornwall Ltd | Construction | 2025 |
| Integrated Ward Williams Associates Ltd | Professional & scientific | 2015 |
| Intent Leadership Ltd | Professional & scientific | 2024 |
| Inter Solutions Ltd | Construction | 2018 |
| Interact Consultancy (UK) Limited | Administrative & support | 1998 |
| Intercurry Limited | Hospitality | 2000 |
| Interiors Smith Ltd | Financial services | 2024 |
| Interventional Radiology Services Limited | Health & social care | 2019 |
| Invest 58 Ltd | Other services | 2021 |
| Invicta EMS Limited | Professional & scientific | 2016 |
| Inyanga Marine Energy Group Limited | Financial services | 2023 |
| Inyanga Maritime Limited | Professional & scientific | 2018 |