| IN Skin Hair & Beauty Clinic Ltd | Other services | 2016 |
| IN Style Group Ltd | Hospitality | 2018 |
| IN the Ring Events Ltd | Arts & recreation | 2017 |
| IN Time Electric Limited | Manufacturing | 2014 |
| IN Time Property Ltd | Real estate | 2022 |
| In-Group Limited | Information & communication | 2018 |
| IN2MINDS.ORG Behavioural Endocrinology Research, Funding and Compliance PVT Ltd | Professional & scientific | 2018 |
| IN2NET(UK) Ltd | Information & communication | 2024 |
| IN2UK Ltd | Manufacturing | 2020 |
| Inachus Ventures Ltd | Information & communication | 2014 |
| Inailer Ltd | Wholesale & retail | 2023 |
| Inani Consulting Ltd | Administrative & support | 2026 |
| Inao Global Ltd | Education | 2018 |
| Inara Global Ltd | Other services | 2025 |
| Inat Marketing Ltd | Wholesale & retail | 2025 |
| Inatthestart Ltd | Agriculture & fishing | 2019 |
| Inavision Construction Ltd | Construction | 2024 |
| Inavision Maintenance Ltd | Construction | 2025 |
| Inaya Idealift Advertising Agency Ltd | Information & communication | 2024 |
| Inayah Health Ltd | Public administration | 2025 |
| Inayat Khan Ltd | Wholesale & retail | 2025 |
| Inboxpro Limited | Information & communication | 2025 |
| Inc & Co Group Ltd | Financial services | 2019 |
| Inc (Management OPS) Ltd | Other services | 2020 |
| Inc (Property Operations) Ltd | Real estate | 2022 |
| Incadesse Ltd | Wholesale & retail | 2017 |
| Ince Convenience Wigan Store Ltd | Wholesale & retail | 2018 |
| Ince Gordon Dadds MAP Limited | Administrative & support | 2016 |
| Ince Gordon Dadds Talent Services Limited | Administrative & support | 2014 |
| Inch Go Lipo & Aesthetics Limited | Health & social care | 2022 |
| Inches Ltd | Wholesale & retail | 2026 |
| Incite Management Ltd | Professional & scientific | 2018 |
| Incitus Limited | Construction | 2019 |
| Included.Ai Limited | Information & communication | 2021 |
| Inclusion Labs Limited | Professional & scientific | 2022 |
| Inclusive Journalism Cymru CIC | Other services | 2022 |
| Incorporated Law Society for Cardiff and District,(The) | Professional & scientific | 1886 |
| Increase the Bookings .COM Ltd | Professional & scientific | 2020 |
| Incremental Business Solutions Ltd | Water & waste | 2015 |
| Incubo Group Ltd | Extraterritorial | 2017 |
| Incubo Holdings Limited | Extraterritorial | 2021 |
| Incubo Ltd | Extraterritorial | 2017 |
| Incurate Limited | Administrative & support | 2016 |
| Indcourt Supplies Limited | Wholesale & retail | 1993 |
| Independent Benefits Services Ltd | Health & social care | 2021 |
| Independent Bodyshop Services Ltd | Wholesale & retail | 2017 |
| Independent Check Limited | Professional & scientific | 2012 |
| Independent Electrical Supplies Limited | Wholesale & retail | 2004 |
| Independent Homecare Services Ltd | Health & social care | 2023 |
| Independent Security Contractor Ltd | Transport & logistics | 2013 |
| Independent Talking Therapies Limited | Health & social care | 2023 |
| Independent Televisions News Limited | Information & communication | 2025 |
| Inderjit SINGH1 Ltd | Construction | 2023 |
| Indermyst Ltd | Construction | 2025 |
| Indesign Fashion Ltd | Wholesale & retail | 2020 |
| Index Invest PC | | 2018 |
| Index Ltd | Information & communication | 2019 |
| Index Services Limited | Transport & logistics | 2020 |
| Indexem LLP | | 2013 |
| India 17 Limited | Hospitality | 2017 |
| India 2 Cardiff Ltd | Hospitality | 2025 |
| India Alexandria Lownds Limited | Extraterritorial | 2019 |
| India Gate ( Cardiff ) Limited | Hospitality | 2011 |
| India Village Ltd | Hospitality | 2019 |
| Indian Attorneys Ltd | Professional & scientific | 2025 |
| Indian Canteen Ltd | Hospitality | 2020 |
| Indian House Ltd | Hospitality | 2025 |
| Indian Junction Ltd | Hospitality | 2025 |
| Indian Saffron Limited | Hospitality | 2019 |
| Indian Street Truck Limited | Hospitality | 2025 |
| Indian Takeaway Ltd | Hospitality | 2019 |
| Indiarasi Limited | Administrative & support | 2013 |
| Indica Beauty Ltd | Wholesale & retail | 2019 |
| Indiel Ltd | Professional & scientific | 2022 |
| Indigo 123 Limited | Financial services | 2023 |
| Indigo Batik International Limited | Wholesale & retail | 2025 |
| Indigo Hair Cardiff Limited | Other services | 2009 |
| Indigo Hearth Limited | Wholesale & retail | 2025 |
| Indigo Medicolegal Consultancies Limited | Health & social care | 2026 |
| Indigo Mountain Limited | Information & communication | 2009 |
| Indigo Post Production Limited | Information & communication | 2019 |
| Indigo Space Limited | Wholesale & retail | 2016 |
| Indigo Wallah Limited | Manufacturing | 2019 |
| Indii Estates Ltd | Real estate | 2022 |
| Indira Piercing Ltd | Other services | 2025 |
| Indish Express Cardiff Ltd | Hospitality | 2024 |
| Indjai Ltd | Professional & scientific | 2019 |
| Indo Cymru Tandoori Restaurant Ltd | Hospitality | 2021 |
| Indo Plant & Equipment Limited | Wholesale & retail | 2021 |
| Indo Supermarket Management Ltd | Wholesale & retail | 2025 |
| Indobritish Academy of Science and Technology Ltd | Education | 2006 |
| Indu Investments Limited | Real estate | 2024 |
| Indus Collective Ltd | Administrative & support | 2019 |
| Indus Unity Healthcare Limited | Health & social care | 2019 |
| Industore Automated Storage Systems Limited | Extraterritorial | 2003 |
| Industore Limited | Wholesale & retail | 1989 |
| Industrial and Catering Industries Limited | Wholesale & retail | 1992 |
| Industrial Cleaners Ltd | Construction | 2024 |
| Industrial Cutting Tools Limited | Manufacturing | 2014 |
| Industrial Machinery Trader Limited | Wholesale & retail | 2025 |