| Homehubrecords Ltd | Information & communication | 2025 |
| Homewoundcare Ltd | Information & communication | 2022 |
| Honour & Co (Fine Jewellery) Ltd | Manufacturing | 2009 |
| Hooked Media Ltd | Information & communication | 2020 |
| Horizon Digital Limited | Other services | 2008 |
| Hornbeam Investments Limited | Real estate | 1997 |
| Hot Sunset Ltd | Other services | 2014 |
| Hotham Park Railway Limited | Transport & logistics | 2017 |
| Hotham Technologies Ltd | Wholesale & retail | 2020 |
| Household Appliance Services Limited | Other services | 2020 |
| Household Appliance UK Ltd | Other services | 2018 |
| HOW to Coffee Ltd | Wholesale & retail | 2017 |
| HR Royale Razor Ltd | Other services | 2026 |
| HUD Electrical Ltd | Construction | 2017 |
| Hudson Supplies Limited | Wholesale & retail | 2022 |
| Hughes Coaching and Therapy Ltd | Health & social care | 2022 |
| Hughes Lewis Consulting Limited | Administrative & support | 2016 |
| Hugo Systems Ltd | Administrative & support | 2022 |
| Hummingbird Insurance Services Ltd | Financial services | 2023 |
| Hummingbird Logistic Services Limited | Transport & logistics | 2020 |
| Humphrey Property Limited | Real estate | 2020 |
| Hungry the Jungle Ltd | Hospitality | 2024 |
| Hunt Electrical Services Ltd | Construction | 2022 |
| Huntington and Barrow Consultants Limited | Information & communication | 2021 |
| Hustlershub Productions Limited | Information & communication | 2026 |
| Hyde Lane Properties Limited | Real estate | 1960 |
| Hydroblitz Ltd | Administrative & support | 2026 |
| Hyper Product Club Ltd | Information & communication | 2022 |
| I D Kiltie Property Maintenance Limited | Construction | 2007 |
| I G C E Ltd | Real estate | 2010 |
| I&V Transport Ltd | Wholesale & retail | 2019 |
| I.M.G. Distribution Limited | Administrative & support | 1996 |
| I.T.S 11 Ltd | Administrative & support | 2017 |
| IAN Gordon Testing Ltd | Construction | 2013 |
| IB2 Food Limited | Hospitality | 2025 |
| IBC Comms Limited | Administrative & support | 2026 |
| IC Ecogreen Solutions Ltd | Wholesale & retail | 2026 |
| Icerinkhireuk Ltd | Arts & recreation | 2019 |
| Iconnic Decor Ltd | Construction | 2023 |
| ID Informatics Limited | Information & communication | 2016 |
| IG UK Builders Ltd | Construction | 2026 |
| IJS Engineering & Construction Ltd | Administrative & support | 2016 |
| Ikoko Consultancy Ltd | Administrative & support | 2023 |
| Illiad Investments Ltd | Financial services | 2018 |
| Illuminari Limited | Professional & scientific | 2021 |
| Illuminated Voices Ltd | Arts & recreation | 2024 |
| IMP Contracting Ltd | Transport & logistics | 2018 |
| Improve Position Limited | Information & communication | 2019 |
| IMS Huntspond Limited | Households | 2020 |
| IN & OUT Property Solution Ltd | Administrative & support | 2025 |
| IN Focus Magazines Ltd | Information & communication | 2024 |
| IN Motion Transport Limited | Transport & logistics | 2023 |
| Incite EQ Limited | Professional & scientific | 2024 |
| Incosol Ltd | Information & communication | 2018 |
| Indigo Management Limited | Professional & scientific | 2000 |
| Infinitee Clothing Limited | Wholesale & retail | 2024 |
| Infra Consultants Ltd | Information & communication | 2025 |
| Inky Leaves Limited | Information & communication | 2025 |
| Inner-Join Limited | Other services | 2002 |
| Innovate Tax Limited | Information & communication | 2012 |
| Innovation Environments Limited | Professional & scientific | 2017 |
| Innovative Measurement Technology Limited | Administrative & support | 2008 |
| Innovative Transport Technologies Limited | Transport & logistics | 2015 |
| Inspirations Hair & Beauty Boutique Ltd | Other services | 2019 |
| Inspireyourlife Limited | Information & communication | 2007 |
| Intelligent Repair Solutions UK Limited | Financial services | 2021 |
| Intercare 2017 Ltd | Health & social care | 2017 |
| Interlet (Sussex) Limited | Real estate | 2008 |
| Interlet Maintenance Services Limited | Manufacturing | 2009 |
| International AI Consultants Ltd | Information & communication | 2025 |
| Internet Aerial Installations Ltd | Information & communication | 2015 |
| Intuitive Edge Limited | Professional & scientific | 2014 |
| Invictus Residential Ltd | Administrative & support | 2024 |
| Io-Gen Studio Ltd | Information & communication | 2022 |
| Iogen Efficiency Limited | Information & communication | 2021 |
| IOK Service Centre Limited | Other services | 2023 |
| Ionian Villas Limited | Administrative & support | 2016 |
| IPH Construction Limited | Extraterritorial | 2012 |
| Iplay Rentals Ltd. | Administrative & support | 2018 |
| Iproducts Limited | Manufacturing | 2024 |
| Iracam Investments Limited | Real estate | 2009 |
| Irwin Heights Management Company Limited | Households | 1993 |
| Ishika Subs Ltd | Hospitality | 2025 |
| ISM Curry Ltd | Hospitality | 2025 |
| Itango Building & Asset Consulting LLP | | 2018 |
| Ivon Blumer Architects Limited | Professional & scientific | 1998 |
| Ixer and Franklin Limited | Construction | 2016 |
| Izmi Property Limited | Real estate | 2024 |
| J & J Aitken Consultancy Limited | Professional & scientific | 2023 |
| J & N Joinery Sussex Limited | Construction | 2024 |
| J 5EA Five Ltd | Wholesale & retail | 2025 |
| J D Dental Technologies Limited | Manufacturing | 2015 |
| J D Dentalengineering Ltd | Professional & scientific | 2012 |
| J K Services (Sussex) Ltd | Wholesale & retail | 2013 |
| J L Newton Limited | Other services | 2020 |
| J M Green Roofing Limited | Construction | 2003 |
| J W Sports Limited | Wholesale & retail | 2000 |
| J Wiley Limited | Professional & scientific | 2013 |
| J&J Team Ltd | Real estate | 2024 |
| J&L Property Limited | Real estate | 2014 |