| Hillman Homes Ltd | Construction | 2017 |
| Hinksy Games Ltd | Wholesale & retail | 2023 |
| HLH Consulting Ltd | Professional & scientific | 2023 |
| Hollow Square Media and Security Ltd | Professional & scientific | 2020 |
| Homely Homes Limited | Extraterritorial | 1985 |
| Homes of Cornwall (West) Ltd | Real estate | 2018 |
| Hot TUB Repair MAN Ltd | Manufacturing | 2024 |
| Howards Business Holdings Ltd | Financial services | 2023 |
| Howards Business Services Ltd | Professional & scientific | 2017 |
| Howards Consulting Ltd | Administrative & support | 2023 |
| Hugafins Co Ltd | Construction | 1995 |
| I D Carter Limited | Construction | 2010 |
| I R Groundworks & Demolition Services Ltd | Administrative & support | 2022 |
| Ibex Heating Ltd | Construction | 2026 |
| Iblast Ltd | Administrative & support | 2025 |
| Ibra Hair Pro Ltd | Wholesale & retail | 2025 |
| IEM Supplies Ltd | Wholesale & retail | 2026 |
| Imagine Stone Limited | Manufacturing | 2023 |
| Implex Construction Ltd | Construction | 2017 |
| Innovate Carpentry and Construction Ltd | Construction | 2024 |
| Innovate for Change Ltd | Professional & scientific | 2023 |
| Interactive Places Limited | Hospitality | 2007 |
| International Mini Store Ltd | Wholesale & retail | 2023 |
| IR Plant Ltd | Construction | 2025 |
| Ireland Bros Limited | Transport & logistics | 2018 |
| Irisco Ltd | Construction | 2024 |
| Isaaks Build Limited | Construction | 2024 |
| J P Tresidder Building Services Ltd | Construction | 2015 |
| J S Kernow Ltd | Wholesale & retail | 2019 |
| Jacob’S Quicktips Limited | Information & communication | 2024 |
| JAM First Property Ltd | Real estate | 2023 |
| James Home Improvements Ltd | Construction | 2024 |
| Jasites Ltd | Information & communication | 2019 |
| Jason Roberts Milk Ltd | Wholesale & retail | 2020 |
| JD Property Cornwall Ltd | Real estate | 2022 |
| JH Cricket Ltd | Manufacturing | 2019 |
| JJ ADV Limited | Construction | 2021 |
| JM Building Services Cornwall Ltd | Construction | 2023 |
| John Beck's Limited | Hospitality | 1963 |
| John Brewer Stairlifts Ltd | Manufacturing | 2016 |
| John Wicks Plant Hire Limited | Construction | 2003 |
| Jones Management Services Limited | Professional & scientific | 2023 |
| Jose SAX Simple Impact Ltd | Information & communication | 2025 |
| Joshuamcconnell Ltd | Arts & recreation | 2025 |
| Jozian Limited | Information & communication | 2011 |
| JRC Care Services Ltd | Health & social care | 2023 |
| Julie Victoria Hichens Limited | Extraterritorial | 2025 |
| Just Pick and MIX Ltd | Wholesale & retail | 2022 |
| Just Stonework Ltd | Construction | 2020 |
| JV Construction (SW) Ltd | Construction | 2024 |
| K C and S J Services Ltd | Administrative & support | 2016 |
| K C Warne Services Ltd | Administrative & support | 2012 |
| Kammbronnfood Limited | Hospitality | 2023 |
| KAR Golden Barbers Ltd | Other services | 2024 |
| Karnview Limited | Financial services | 2026 |
| Kath's Plaice Ltd | Hospitality | 2019 |
| Kazmia Technologies Limited | Wholesale & retail | 2024 |
| Kehelland Community Interest Company | Health & social care | 2016 |
| Kehelland Horticultural Centre Limited | Agriculture & fishing | 1983 |
| Keltek Property Ltd | Real estate | 2026 |
| Keltek-Offshore Ltd | Construction | 2022 |
| Kemp Associates Limited | Arts & recreation | 2003 |
| Kemp International Limited | Information & communication | 2017 |
| Kemp Sales Limited | Hospitality | 2016 |
| Kenaz Ltd | Professional & scientific | 2023 |
| Kendall Financial Ltd | Construction | 2025 |
| Kernow Active CIC | Health & social care | 2025 |
| Kernow Concierge Services Limited | Administrative & support | 2022 |
| Kernow Maritime Services Limited | Professional & scientific | 2005 |
| Kernow Rally Experience LLP | | 2022 |
| Killivose Homes Ltd | Real estate | 2026 |
| Killy Developments Ltd | Construction | 2021 |
| Knowplace Ltd | Information & communication | 2024 |
| Konstruct Campers Ltd | Manufacturing | 2022 |
| Konstruct Cornwall Ltd | Construction | 2013 |
| KP Construction (Cornwall) Limited | Construction | 2014 |
| L E Holdings Group Ltd | Real estate | 2024 |
| L Manna Carpentry Ltd | Construction | 2022 |
| Lady Drive (Camborne) Residents Company Limited | Other services | 2018 |
| Lamb's Lectrics LLP | | 2014 |
| Lamp Accounting Ltd | Professional & scientific | 2024 |
| Land Consultants (London) Ltd | Real estate | 2020 |
| Land Consultants Holdings Limited | Financial services | 2026 |
| Landmark Architectural Design Ltd | Professional & scientific | 2016 |
| Langley's (Cornwall) Ltd | Financial services | 2022 |
| Lanner Equestrian Centre Ltd | Agriculture & fishing | 2010 |
| Laurence Butler Limited | Manufacturing | 1981 |
| Lawry Building & Maintenance Limited | Construction | 2008 |
| LCA Cornwall Ltd | Hospitality | 2026 |
| LCM Cornwall Ltd | Hospitality | 2022 |
| Leaders Septic Tank Emptying Cornwall Ltd | Water & waste | 2020 |
| Lello Bros. Limited | Agriculture & fishing | 1945 |
| LEM Carpentry Limited | Construction | 2015 |
| Lemsley Limited | Wholesale & retail | 2025 |
| Liam Thomas Independent Financial Advisor Ltd | Financial services | 2022 |
| Lightupglo CIC | Health & social care | 2024 |
| Limehome Properties Limited | Hospitality | 2003 |
| Limitless Wellbeing Ltd | Health & social care | 2025 |
| Lissipan Ltd | Education | 2018 |
| Live Fire Limited | Agriculture & fishing | 2023 |