| Heat Elite Cardiff Ltd | Construction | 2024 |
| Heat Pump Retail Limited | Wholesale & retail | 2025 |
| Heat Recruitment Limited | Administrative & support | 2023 |
| Heat Safe Cardiff Ltd | Construction | 2018 |
| Heat-King Building Maintenance Ltd | Construction | 2017 |
| HEAT2COOL Engineering Ltd | Administrative & support | 2017 |
| Heatcare (Cardiff) Ltd | Construction | 2013 |
| Heatcoal Limited | Extraterritorial | 2012 |
| Heatech Ltd | Wholesale & retail | 2021 |
| Heatglow Limited | Wholesale & retail | 2024 |
| Heath Auto Service Ltd | Wholesale & retail | 2025 |
| Heath Halt Court (Cardiff) Management Company Limited | Households | 2004 |
| Heath Hotel Partnership Ltd | Hospitality | 2024 |
| Heath Marketing Limited | Professional & scientific | 2008 |
| Heath Motor Co. Ltd. | Wholesale & retail | 2003 |
| Heath One Group Ltd | Wholesale & retail | 2024 |
| Heath Property Investments Limited | Real estate | 1966 |
| Heath Roofing Service Ltd | Construction | 2022 |
| Heath Trade Plastics Ltd | Extraterritorial | 2021 |
| Heath Trade Supply Limited | Wholesale & retail | 2024 |
| Heath Tyres Auto Centre Ltd | Wholesale & retail | 2016 |
| Heath Windows and Doors Ltd. | Construction | 2011 |
| Heathercroft Training Services Limited | Education | 2001 |
| Heatherwood Court Limited | Health & social care | 1996 |
| Heathfields Residential Homes Limited | Hospitality | 1986 |
| Heathrow Airport Meet Greet Ltd | Information & communication | 2026 |
| Heathrow General Cars Ltd | Wholesale & retail | 2014 |
| Heathwood Carpets and Flooring Limited | Wholesale & retail | 2018 |
| Heathwood Childrens Swimming Academy Ltd | Education | 2022 |
| Heathwood Electrics Ltd | Construction | 2021 |
| Heathwood Swimming Limited | Arts & recreation | 2023 |
| Heathwood Triathlon Ltd | Arts & recreation | 2026 |
| Heating & Plumbing Warehouse Limited | Wholesale & retail | 2001 |
| Heating Cardiff Limited | Professional & scientific | 2016 |
| Heaton Halal Superstore Ltd | Wholesale & retail | 2017 |
| Heatright SW Ltd | Construction | 2019 |
| Heatsafe 247 Ltd | Construction | 2024 |
| HEAVE2 Limited | Financial services | 2022 |
| Heaven Scent Angels Limited | Administrative & support | 2016 |
| Heavenly Dezign Ltd | Professional & scientific | 2023 |
| Heavenly Hair Extensions Ltd | Wholesale & retail | 2023 |
| Heavenly Hope Ltd | Other services | 2018 |
| Heavenly NET Treasure Ltd | Information & communication | 2017 |
| Heavenly Perfumes Limited | Wholesale & retail | 2023 |
| Heaven’S Kitchen Ltd | Hospitality | 2019 |
| Heavitree Spice Limited | Hospitality | 2023 |
| Heavy Transport Limited | Transport & logistics | 2014 |
| Heavydutycosmetics Ltd | Wholesale & retail | 2021 |
| HEB 20 Limited | Information & communication | 2020 |
| Hebden Waterside Limited | Professional & scientific | 2005 |
| Hebeyg Limited | Wholesale & retail | 2018 |
| Hecate Verona Ltd | Wholesale & retail | 2013 |
| Hecate's Hideout Ltd | Hospitality | 2021 |
| Hecsagon Ltd | Real estate | 2017 |
| Heda Chemical Fiber (UK) Limited | Manufacturing | 2021 |
| Hedfanco Ltd | Professional & scientific | 2023 |
| Hedge Trimming Cardiff Limited | Administrative & support | 2022 |
| Hedgehog Invest Limited | Professional & scientific | 2021 |
| Hedges 1 Limited | Information & communication | 2015 |
| Hedone Bakery Limited | Manufacturing | 2017 |
| Hedonism Travel Ltd | Administrative & support | 2017 |
| Hedtech Ltd | Administrative & support | 2016 |
| Heels Empowerment Limited | Education | 2021 |
| Heelts Ltd | Wholesale & retail | 2025 |
| Hefei Research Silicone Technology Co., Ltd. | Administrative & support | 2022 |
| Hegemonic Enterprises Limited | Administrative & support | 2016 |
| Heidelberg Recycling Machinery Limited | Administrative & support | 2014 |
| Heights Estate Agents Limited | Real estate | 2019 |
| Heiligensee AG | Professional & scientific | 2022 |
| Heimdalloutdoor by Rudi Andresen Heimdahl Limited | Extraterritorial | 2025 |
| Heiq Trading Ltd | Professional & scientific | 2014 |
| Heist Restaurants Limited | Hospitality | 2004 |
| HEK Jones Limited | Professional & scientific | 2014 |
| Hekla Development Ltd | Information & communication | 2021 |
| Helal Sahak Ltd | Wholesale & retail | 2025 |
| Heledd Fflur Ltd | Administrative & support | 2025 |
| Helen Agape Limited | Real estate | 2025 |
| Helen Court Management Company Limited | Households | 1988 |
| Helen Gorman Ltd | Education | 2013 |
| Helen Huxford Legal Ltd | Professional & scientific | 2020 |
| Helen Iles Limited | Professional & scientific | 2017 |
| Helen Industry and Trade Co., Limited | Extraterritorial | 2018 |
| Helen Mahoney Consultancy Ltd | Professional & scientific | 2021 |
| Helen Phillips Business Solutions Ltd | Professional & scientific | 2017 |
| Helen's Nails Limited | Other services | 2021 |
| Helena Health Ltd | Manufacturing | 2025 |
| Helensmom Ltd | Wholesale & retail | 2024 |
| Helevol Ltd | Construction | 2018 |
| Helianthus Holding Ltd | Professional & scientific | 2024 |
| Helianthus Media Limited | Information & communication | 2021 |
| Helio Group Limited | Financial services | 2017 |
| Helio Technologies Ltd | Information & communication | 2020 |
| Helios Construction Services Ltd | Construction | 2014 |
| Helios Cosmetics Limited | Wholesale & retail | 2020 |
| Helios Global Ventures Limited | Real estate | 2015 |
| Helix Limited | Administrative & support | 2023 |
| Helix Renewable Energy Services Ltd | Administrative & support | 2022 |
| Helix Sight Technologies Ltd | Information & communication | 2025 |
| Hello Business Research Limited | Administrative & support | 2016 |
| Hello Investment Ltd | Information & communication | 2021 |