| Husseys (SW) Ltd | Wholesale & retail | 2021 |
| Hutchings Groundworks and Plant Hire Ltd | Construction | 2012 |
| Hutton Investments Ltd | Real estate | 2024 |
| Hutton Jabbari Ltd | Real estate | 2026 |
| Huxbear Biofuels Ltd | Agriculture & fishing | 2012 |
| Huxnor Ltd | Education | 2025 |
| Hybrid and Virtual Events Ltd | Extraterritorial | 2018 |
| Hyde-Hart Consulting Ltd | Hospitality | 2021 |
| Hyperion Info SEC Limited | Administrative & support | 2015 |
| Hyperlink Limited | Professional & scientific | 2000 |
| Hyres Geoscience Solutions Ltd | Professional & scientific | 2015 |
| Hyson Properties Limited | Hospitality | 2018 |
| I Wish World Limited | Other services | 2011 |
| I.C.E. Consulting (S.E.) Limited | Real estate | 2014 |
| I2 Controls Ltd | Other services | 2013 |
| IAN Barnard Architecture Limited | Professional & scientific | 2021 |
| IAN Wills Limited | Real estate | 2016 |
| Ianvanpod Ltd | Hospitality | 2012 |
| Ibounce Newton Abbot Limited | Arts & recreation | 2016 |
| IC Copier Solutions Ltd | Information & communication | 2006 |
| Ice on Fire Limited | Wholesale & retail | 2000 |
| Icho Investments Ltd | Construction | 2020 |
| Ickle Pickles Sensory,Soft Play & Events. Limited | Administrative & support | 2024 |
| Icrow Limited | Real estate | 2025 |
| Idream Solutions Construction Limited | Construction | 2014 |
| Idream Solutions Limited | Construction | 2013 |
| IFF Holdings Limited | Financial services | 2026 |
| Igloo Ventures Ltd | Households | 2025 |
| Ignitepro Services Ltd | Construction | 2025 |
| IHM Heathfield Ltd | Households | 2024 |
| Illustration (2005) Limited | Real estate | 1996 |
| Illustration Limited | Professional & scientific | 2005 |
| IMA Marine Ltd | Professional & scientific | 2011 |
| Imagine and Believe Limited | Information & communication | 2021 |
| Imagine That Limited | Information & communication | 2008 |
| Imec SW Ltd | Construction | 2023 |
| Impact Golf Club Ltd | Wholesale & retail | 2026 |
| Impactful Sourcing and Coaching Solutions Ltd | Wholesale & retail | 2020 |
| IN the Room Global Ltd | Information & communication | 2017 |
| In-Sight Imaging Systems Ltd | Professional & scientific | 2017 |
| IN2LIFE Limited | Arts & recreation | 2020 |
| Inca Property Group Ltd | Real estate | 2017 |
| Incore UK Limited | Manufacturing | 2025 |
| Independent Family Assessments Ltd | Health & social care | 2021 |
| Independent PH Consultancy Ltd | Administrative & support | 2016 |
| India Florence Ltd | Professional & scientific | 2024 |
| Indulgence Tea Rooms Limited | Hospitality | 2019 |
| Industrial Extraction Services Ltd | Professional & scientific | 2013 |
| Inet Marketeers Ltd | Information & communication | 2014 |
| Infinite Spirit Sounds Ltd | Arts & recreation | 2017 |
| Infinity Homes South West Ltd | Real estate | 2021 |
| Infinity Property Management (SW) Limited | Real estate | 2019 |
| Infinity Retreats Limited | Arts & recreation | 2024 |
| Infinity Salon Torquay Ltd | Other services | 2024 |
| Infinity Training Club Limited | Manufacturing | 2023 |
| Infra 360 CIC | Professional & scientific | 2026 |
| ING & Brierley Limited | Hospitality | 2023 |
| Inghams Anaesthesia Limited | Health & social care | 2011 |
| Ingrid Mostyn Limited | Professional & scientific | 2014 |
| Inline Kitchens (Newton Abbot) Limited | Construction | 2003 |
| Innco Limited | Hospitality | 2000 |
| Inner Circle Recordings Ltd | Wholesale & retail | 2023 |
| Inno-Tech Electrical and Renewable Solutions Ltd | Construction | 2023 |
| Innovate Designs Ltd | Wholesale & retail | 2014 |
| Innovative Property Group Ltd | Professional & scientific | 2014 |
| Insanity Arcade Devon Ltd | Arts & recreation | 2025 |
| Insight Productions Limited | Information & communication | 1982 |
| Inspired Disability Awareness Ltd | Health & social care | 2020 |
| Instant Capital Ltd | Financial services | 2014 |
| Instar Construction Ltd | Construction | 2024 |
| INSUL8 SW Ltd | Construction | 2024 |
| Insulated Homes Limited | Construction | 2010 |
| Insurelab Ltd | Information & communication | 2025 |
| Integral Digital Technologies Ltd | Information & communication | 2021 |
| Integrale Technical Services Ltd | Manufacturing | 1998 |
| Integrate Systems Consulting Limited | Professional & scientific | 2023 |
| Intellek Ltd | Information & communication | 1989 |
| Intellitender Limited | Professional & scientific | 2016 |
| Intera Consultancy Ltd | Professional & scientific | 2017 |
| Interbe Limited | Professional & scientific | 2010 |
| Interior Design and Property Solutions Ltd | Construction | 2024 |
| Interiors Inside OUT Ltd | Professional & scientific | 2018 |
| International Dance Supplies Limited | Wholesale & retail | 2005 |
| International House Management Limited | Other services | 2017 |
| International Property Consultancy LLP | | 2015 |
| Interwise Ltd | Professional & scientific | 2026 |
| Intproco LLP | | 2022 |
| Intrinsic Design and Build Ltd | Construction | 2019 |
| Introspec Developments Ltd | Professional & scientific | 2018 |
| Intuition Training and Development Limited | Education | 2023 |
| Inventex Limited | Construction | 2012 |
| Inventive Limited | Information & communication | 2018 |
| Invertere Coat Company Limited(The) | Wholesale & retail | 1949 |
| Invest Health Ltd | Information & communication | 2022 |
| Investment & Financial Solutions Partnership LLP | | 2010 |
| Investor Ready IP Ltd | Professional & scientific | 2026 |
| Invicta Properties (Southwest) Ltd | Real estate | 2015 |
| Invictus Consultants Limited | Information & communication | 2014 |
| Invisiona Ltd | Information & communication | 2013 |
| Iona Group Holdings Ltd | Financial services | 2024 |