| Geocubed Limited | Mining & quarrying | 2020 |
| Gibson and Collins Programming/Nutrition LP | | 2020 |
| Giles Plant Hire Limited | Administrative & support | 2002 |
| Gillett's (Callington) Limited | Wholesale & retail | 1986 |
| Gist (Insurance Brokers) Limited | Financial services | 1952 |
| Glebe Properties (Cornwall) Limited | Real estate | 2006 |
| Glebe Quarry Limited | Water & waste | 1997 |
| Global Advanced Recycling Technology Company Limited | Water & waste | 2001 |
| Globe Vale Holiday Park Limited | Hospitality | 2007 |
| GMS Leisure Ltd | Construction | 2002 |
| Go Stump NO Stump Limited | Agriculture & fishing | 2002 |
| Goodenough(St Austell)Limited | Wholesale & retail | 1964 |
| Goonhilly Holdings Ltd | Financial services | 2018 |
| Goonvrea Court Limited | Households | 1967 |
| GPJ Consulting Engineers Limited | Professional & scientific | 2002 |
| Grahams Garden Machinery Ltd | Manufacturing | 2007 |
| Grasmere Structural Engineers Limited | Professional & scientific | 2003 |
| Green Peninsula Co Limited | Professional & scientific | 2000 |
| Greenperch Property Management Limited | Households | 2003 |
| Grosvenor House Associates (Cornwall) Limited | Administrative & support | 1989 |
| Gunnards House (Redruth) Management Company Limited | Households | 1993 |
| GW Smart Consultancy Ltd | Professional & scientific | 2022 |
| H G Richards Limited | Construction | 2011 |
| H K P Estates Ltd | Construction | 2021 |
| H.Freemantle & SON Limited | Real estate | 1960 |
| Hair IT IS Limited | Other services | 2005 |
| Harbour Court (Portscatho) Management Company Limited | Households | 2002 |
| Harbour Holidays Limited | Real estate | 2003 |
| Harver Enterprises Limited | Extraterritorial | 2006 |
| Harvey's Foundry Trust | Arts & recreation | 2003 |
| Haven Kitchens Ltd | Wholesale & retail | 2024 |
| Hawkins Holdings Limited | Wholesale & retail | 2007 |
| Hayle Taxis Limited | Transport & logistics | 2003 |
| Hayle Veterinary Limited | Professional & scientific | 2016 |
| Headland Hotel Company Limited(The) | Hospitality | 1973 |
| Headlines (Launceston) Limited | Other services | 2002 |
| Heligan Development Limited | Real estate | 1969 |
| Hendra Bakeries Limited | Manufacturing | 1960 |
| Heyworth's Farm Buildings Limited | Construction | 2004 |
| Highfield Park (Bodmin) Management Company Limited | Households | 2022 |
| HMC Associates Limited | Professional & scientific | 1995 |
| Homefield PAR Management Company Limited | Households | 1997 |
| Homeleigh Garden Centre Limited | Wholesale & retail | 2002 |
| Hooton Consultancy Services Ltd | Professional & scientific | 2006 |
| Horizon Mobility Ltd | Manufacturing | 2006 |
| Howe & Coad Ltd | Construction | 2021 |
| Howton Contractors Limited | Administrative & support | 2003 |
| Huggins Bro's Marine Limited | Administrative & support | 2008 |
| I.S.A.Partnership | | 1979 |
| IAN Richards (West Country Construction) Limited | Construction | 2004 |
| IES Phipps Roofing Contractors Limited | | 1988 |
| Incandescence Production Company Limited | Arts & recreation | 2002 |
| Independent Aviation Safety (IAS) UK Limited | Professional & scientific | 2005 |
| Innovation Management Limited | Professional & scientific | 2024 |
| Inspire Makers Ltd | Wholesale & retail | 2019 |
| Irons Brothers,Limited | Manufacturing | 1930 |
| Isell Ltd | Administrative & support | 2005 |
| Iteracy Limited | Information & communication | 2007 |
| J & J Kerkin Agri Limited | Agriculture & fishing | 2022 |
| J & S Farms Trewidden Limited | Agriculture & fishing | 1999 |
| J a Hollow & Co Limited | Professional & scientific | 2002 |
| J Behennah Limited | Construction | 2005 |
| J C Mitchell Builders Limited | Construction | 2001 |
| J M Brewer Limited | Construction | 1999 |
| J O Nightingale Limited | Agriculture & fishing | 2008 |
| J.C.Williams & Sons(Furnishers)Limited | Wholesale & retail | 1962 |
| J.S.Construction(St.Austell)Limited | | 1972 |
| J.T.Howard Properties Limited | Real estate | 1965 |
| Jackie Stanley Limited | Real estate | 2003 |
| James Handley Ltd | Administrative & support | 2017 |
| Jamies Pasty Shop Limited | Manufacturing | 2003 |
| Jaquemand Limited | | 1986 |
| Jetset Software Limited | Information & communication | 1993 |
| Joanna Limited | Professional & scientific | 1995 |
| Jobel Engineering Limited | Manufacturing | 1976 |
| Joce Partnership | | 2001 |
| JOG Safety, Workwear & Leisure Limited | Wholesale & retail | 2006 |
| John Nicholls Funeral Service Ltd. | Other services | 1993 |
| Joy Williams Limited | Extraterritorial | 1962 |
| JTM Systems Limited | Information & communication | 2000 |
| Julia & Julia Ltd | Wholesale & retail | 2012 |
| Just Software Solutions Limited | Information & communication | 2005 |
| K Williams Motorcycles Limited | Wholesale & retail | 2002 |
| K.E. Telecommunication Limited | | 1985 |
| Kanso Studio Ltd | Professional & scientific | 2024 |
| Karenza Property Ltd | Real estate | 2022 |
| Karn Solutions Ltd | Information & communication | 2006 |
| Karona Games Ltd | Wholesale & retail | 2002 |
| Karrek Accountants Limited | Professional & scientific | 2006 |
| Karrek Financial Management Limited | Financial services | 2005 |
| Keith Cheesewright Caravans Ltd | Wholesale & retail | 2002 |
| Kellaway's Fish and Chips Ltd | Hospitality | 2003 |
| Keltic Funding Limited | | 1990 |
| Kernock Park Plants Limited | Agriculture & fishing | 1996 |
| Kernow Model Rail Centre Limited | Wholesale & retail | 2002 |
| Kernow Property Services Ltd | Real estate | 2004 |
| Keskerdh Kernow Limited | Education | 1996 |
| Keveral Farmers Limited | Agriculture & fishing | 1991 |
| Kevin Harris Limited | Construction | 2006 |
| Kilbirnie Hotel Ltd | Hospitality | 2017 |