| Happ Technology Ltd | Mining & quarrying | 2007 |
| Harbour House Flushing Limited | Hospitality | 2023 |
| Harbour Lights (Cornwall) Limited | Hospitality | 2002 |
| Harding & Wakefield Group Ltd | Financial services | 2025 |
| Harding and Wakefield Ltd | Real estate | 2016 |
| Harris and Sampson Ltd | Real estate | 2013 |
| Harvenna View Management Company Limited | Households | 2024 |
| Hayle Golf Ltd | Arts & recreation | 2008 |
| Head Hunter Resourcing Limited | Administrative & support | 2019 |
| Healdon Holdings Limited | Real estate | 1976 |
| Helford Hotels Holdings Limited | Financial services | 1987 |
| Helford Passage Apartments Limited | Households | 2009 |
| Helford Powerboat Charters Limited | Other services | 2019 |
| Helford Properties Limited | Real estate | 1950 |
| Helford River Distillery Ltd | Manufacturing | 2016 |
| Heli REP Ltd | Manufacturing | 2020 |
| Hello Realign Ltd | Professional & scientific | 2026 |
| Help at Home Care Service Ltd | Health & social care | 2014 |
| Henry Swanzy Limited | Manufacturing | 1999 |
| Herd Alpha Ltd | Financial services | 2026 |
| Hetco Design Ltd | Professional & scientific | 2017 |
| Hewitt-Boorman Land and Property Ltd | Real estate | 2022 |
| HHP Properties Limited | Real estate | 2025 |
| High Potential Limited | Extraterritorial | 2015 |
| High Water Films Limited | Information & communication | 2021 |
| Hirst Magnetic Instruments Limited | Manufacturing | 1981 |
| HIT Power Limited | Professional & scientific | 2014 |
| HLR Construction Law Services Ltd | Professional & scientific | 2023 |
| Hocking Fire & Electrical Ltd | Construction | 2023 |
| Holmes Enterprises Limited | Wholesale & retail | 2001 |
| Holmes Housing Ltd | Hospitality | 2011 |
| Homes by Mollie Ltd | Administrative & support | 2023 |
| Hornbeam Court Management Limited | Real estate | 2000 |
| Hotel Build Management Ltd | Professional & scientific | 2020 |
| Hotelo Limited | Hospitality | 2006 |
| House of Aazaadee Ltd | Wholesale & retail | 2024 |
| House of Denim Ltd | Wholesale & retail | 2019 |
| Housman Hotels Limited | Hospitality | 2012 |
| Hub KB Limited | Wholesale & retail | 2016 |
| Hughes Heating & Plumbing Cornwall Ltd | Construction | 2026 |
| Humanity Collective Ltd | Wholesale & retail | 2024 |
| Hungry Billy Ltd | Information & communication | 2021 |
| Hurdlesgrove Hill Ltd | Professional & scientific | 2012 |
| Hydro Motion Media CIC | Information & communication | 2016 |
| I AM a Keeper Limited | Professional & scientific | 2022 |
| I H S Decorators Limited | Construction | 2008 |
| I Said IT Ltd | Real estate | 2018 |
| Ialr Engineering Limited | Mining & quarrying | 2012 |
| IAN Churcher Ltd | Construction | 2003 |
| IAN Drennan Building Contractor Ltd | Construction | 2015 |
| IAN Moseley Accountancy Services Ltd | Professional & scientific | 2014 |
| IAP Plumbing and Heating Services Ltd | Construction | 2021 |
| Ice Trikes Trustees Limited | Professional & scientific | 2022 |
| Idealitymedia Ltd | Information & communication | 2021 |
| IHS Drywall Limited | Construction | 2023 |
| Imogen Reeve & Co. CIC | Arts & recreation | 2023 |
| Improving Procurement Ltd | Administrative & support | 2011 |
| Indy Quinn LLP | | 2021 |
| Infinitus Security & Training Limited | Administrative & support | 2012 |
| Infinity Chiropractic Ltd | Health & social care | 2016 |
| Innisfail Limited | Professional & scientific | 2016 |
| Insight Mortgages Ltd | Financial services | 2013 |
| Inspiration Yacht Fairing Limited | Manufacturing | 2007 |
| Inspire Sailing Limited | Other services | 2024 |
| Inspired Cycle Engineering Limited | Manufacturing | 1998 |
| Intelecsouthwest Ltd | Manufacturing | 2022 |
| Intelligent AID Limited | Extraterritorial | 2017 |
| Intercontinental Brands Group Limited | Financial services | 2023 |
| Intercontinental Spirits Limited | Wholesale & retail | 2023 |
| Interface Insight Limited | Professional & scientific | 2024 |
| Internal Garden Ltd | Information & communication | 2022 |
| International Maral Northern Consultancy Ltd | Wholesale & retail | 2025 |
| International Sea Kayak Guide Alliance Ltd | Education | 2023 |
| International Superyacht Coatings Group Limited | Financial services | 2022 |
| International Superyacht Coatings Limited | Other services | 2007 |
| Intertidal Timber Ltd | Construction | 2024 |
| Involve IP Ltd | Professional & scientific | 2026 |
| Irene DEL VAL Ltd | Other services | 2025 |
| Isobel's of Mylor Limited | Hospitality | 2026 |
| IT Services & Sales Limited | Information & communication | 1994 |
| IVF Limited | Professional & scientific | 2010 |
| Ivfsynergy Ltd | Administrative & support | 2016 |
| J & T Webster Services Ltd | Health & social care | 2014 |
| Jack Blackburn Electrical Ltd | Construction | 2017 |
| Jack Gifford Naval Architect Limited | Professional & scientific | 2016 |
| Jacksons Superyacht Finishers Ltd | Manufacturing | 2014 |
| JAM Land & Property Ltd | Real estate | 2017 |
| JAM Sandwich Limited | Professional & scientific | 2014 |
| James Hodgson Limited | Professional & scientific | 2021 |
| James Pascoe Engineering Ltd | Professional & scientific | 2016 |
| Jamie Medlin Marine Art Limited | Arts & recreation | 2008 |
| Jarrang Limited | Professional & scientific | 2003 |
| Jarvis Property Maintenance and Energy Assessors Ltd | Construction | 2023 |
| Jaxwax Ltd | Manufacturing | 2025 |
| Jazzimation Studios Limited | Other services | 2019 |
| Jbkg Holdings Ltd | Real estate | 2020 |
| JD Services (Gloucester) Ltd | Other services | 2016 |
| Jdhay Films Ltd | Information & communication | 2024 |
| Jeremy Whitaker Consultancy Limited | Professional & scientific | 2018 |
| JHL Media LLP | | 2025 |