| Intern London Limited | Fitzrovia | 2011 |
| Internal Coaching Academy Ltd | London | 2024 |
| International School of Human Studies Ltd | London | 2021 |
| International Academic Centre Limited | Manchester | 2017 |
| International Academic Journals Limited | Maidstone | 2026 |
| International Academic Projects Limited | | 1989 |
| International Academy for Advanced Research and Studies Ltd | London | 2010 |
| International Academy for Higher Studies Ltd | Liverpool | 2024 |
| International Academy for Integrative Medicine Sciences Limited | London | 2024 |
| International Academy for Leadership and Socio-Economic Development Ltd | Bolton | 2026 |
| International Academy for Professional Development Limited | Hitchin | 2010 |
| International Academy for Traditional Tibetan Medicine (UK) Limited | London | 2012 |
| International Academy of Aesthetic Innovation Ltd | London | 2026 |
| International Academy of Aesthetics Limited | London | 2016 |
| International Academy of Applied Finance and Investment Ltd | London | 2025 |
| International Academy of Billiards, Snooker and Mind Games Ltd | Cardiff | 2024 |
| International Academy of Chinese Culinary Arts Ltd | Cardiff | 2019 |
| International Academy of Directors Ltd | London | 2020 |
| International Academy of Education & Training Limited | Brighton | 2022 |
| International Academy of Health Care Training Ltd | Salford | 2025 |
| International Academy of London Ltd | Morden | 2013 |
| International Academy of Sciences and Humanities Limited | London | 2015 |
| International Academy of Secrets Wisdom Ltd | London | 2025 |
| International Academy of Xunzhen Meridian Palpation Therapeutics Limited | Norwich | 2024 |
| International Ades College Ltd | Cardiff | 2025 |
| International Admissions Ltd | Bury | 2025 |
| International Advocacy Academy | London | 2013 |
| International African Institute | London | 2000 |
| International Air Cadet Training | Herne Bay | 2010 |
| International Alliance of Churches and Ministers (Intacam) | Gravesend | 2016 |
| International American Board Ltd | London | 2024 |
| International Arts Partnership | Heathfield | 2016 |
| International Assembly of Contemporary Teachers Ltd | London | 2021 |
| International Assessor Board for Professionals Limited | Essex | 2025 |
| International Associat of Maritime Professionals Ltd | London | 2024 |
| International Association for Applied Econometrics | Cambridge | 2011 |
| International Association for Comparative Research on Leukemia and Related Diseases Ltd | London | 2025 |
| International Association for Digital Publications | Royston | 2004 |
| International Association for Relational Transactional Analysis | Aylesbury | 2009 |
| International Association for Sustainable Economy | London | 2020 |
| International Association for the Study of Child Language | Duns | 2007 |
| International Association of Electoral Training Organisations | London | 2015 |
| International Association of Accounting Professionals | London | 2008 |
| International Association of Management Accountants | Birmingham | 2024 |
| International Association of Maritime Institutions | Southampton | 2013 |
| International Aviation Academy-Norwich Ltd | Norwich | 2015 |
| International Awards Board Limited | Manchester | 2020 |
| International Baccalaureate Fund (UK) | Cardiff | 2008 |
| International Basketball Academy Ltd | Macclesfield | 2025 |
| International Beauty Academy Limited | Liverpool | 2016 |
| International Board for Education and Culture Ltd | London | 2024 |
| International Board for Education and Training Ltd | London | 2024 |
| International Board of Education Excellence Ltd | London | 2025 |
| International Board of Skills & Development -UK Ltd | London | 2026 |
| International Board of Vocational Training and Qualification Ltd Ltd | Manchester | 2021 |
| International Boxing Kickboxing Organisation Ltd | Rossendale | 2020 |
| International British Development Experts Academy Limited | High Wycombe | 2019 |
| International British Online School Ltd | London | 2019 |
| International British School Ltd | London | 2023 |
| International British Theatre School Ltd | Manchester | 2018 |
| International Broadcasting Trust | 82 Tanner Street | 2012 |
| International Budo Federation (UK) Limited | Lowestoft | 2025 |
| International Business Academy Consortium Ltd | Glasgow | 2020 |
| International Business College Manchester Limited | Manchester | 2011 |
| International Business School Ltd | Sale | 2022 |
| International Business Studies Ltd | Northampton | 2023 |
| International Camp Suisse Ltd | Leeds | 2011 |
| International Camp World Ltd | London | 2018 |
| International Cancer Imaging Society | London | 2000 |
| International Careers Network Ltd | Mildenhall | 2024 |
| International Cass Academy Ltd | Ilford | 2021 |
| International Cat Care | Salisbury | 2006 |
| International Center for Music Grading Ltd | Beckenham | 2023 |
| International Center for Scientific Research and Studies Ltd | London | 2025 |
| International Centre for Aerospace Training Limited | Cardiff | 2006 |
| International Centre for Coaching and Mentoring Ltd | London | 2025 |
| International Centre for Coaching in Education Ltd | Halifax | 2020 |
| International Centre for Creative and Cultural Industries Ltd | London | 2026 |
| International Centre for Jewish Studies | London | 2015 |
| International Centre for Parliamentary Studies Limited | London | 2010 |
| International Centre for Policy Studies Limited | London | 2023 |
| International Centre for Responsible Tourism Global CIC | Crawley | 2024 |
| International Centre of Contemporary Research in Islamic Sciences Ltd | Harlow | 2022 |
| International Centre of Excellence Ltd | Manchester | 2020 |
| International Centre of Persian Lecturers and Teachers Limited | London | 2025 |
| International Centre of Safety Professionals (Icsp) PVT Ltd | Ruislip, | 2025 |
| International Ceramics Festival Ltd | Penglais | 2020 |
| International Certificate of Christian Education Limited | Oxford | 2009 |
| International Certification Body for Continuous Improvement Professionals Ltd | London | 2025 |
| International Certification Ltd | Ruislip | 2019 |
| International Chamber of Sustainable Development (UK) | London | 2022 |
| International Christian Youthworks Company Limited | Othery | 2005 |
| International Clinical Analytical and Scientific Services Ltd | Cowes | 2022 |
| International Coaching Limited | Ashton-Under-Lyne | 2014 |
| International Coaching Solutions Limited | St. Helens | 2018 |
| International College for Exercise Professionals Limited | Ipswich | 2021 |
| International College London Ltd | London | 2024 |
| International College of Aesthetic Medicine (Icam) Ltd | Sutton Coldfield | 2018 |
| International College of Contemporary Sciences Ltd | Rainham | 2025 |
| International College of Education and Training Limited | London | 2018 |