| International KHO KHO Federation | Iver | 2018 |
| International Language College Ltd | Newcastle Upon Tyne | 2022 |
| International Language Homestays Limited | Broadstairs | 2012 |
| International Language Services Limited | Poole | 2019 |
| International Law Summits Ltd | London | 2019 |
| International Lawyers Project | London | 2005 |
| International Leadership Centre Ltd | London | 2024 |
| International Lean SIX Sigma Academy Ltd | Cambridge | 2017 |
| International Learning Alliance Limited | Wallasey | 2016 |
| International Learning Exchange Programme Limited | Cardiff | 2021 |
| International Learning Pathways (ILP) Limited | London | 2025 |
| International Legal AID Ltd | Manchester | 2025 |
| International Links (Global) Ltd | Cardiff | 2018 |
| International Live Events Group Limited | Aberystwyth | 2020 |
| International Longevity Science & Research Association | Cambridge | 2025 |
| International Mathematics Competition Ltd | London | 2020 |
| International Medical Board for Business Skills Ltd. | London | 2023 |
| International Medical Education Ltd. | London | 2013 |
| International Medical Studies Ltd | Wembley | 2022 |
| International Medical Training Academy Limited | London | 2015 |
| International Migrants Organisation for Development and Prosperity Ltd | Twickenham | 2019 |
| International Ministers Fellowship | London | 2007 |
| International Ministries for the Living Word | London | 1994 |
| International Mixed Ability Sports C.I.C. | Bradford | 2014 |
| International Movement for Tamil Culture Imtc | Hornchurch | 2020 |
| International Music Examinations Association | Beckenham | 2021 |
| International Music Solutions Ltd | London | 2018 |
| International Nails Hair Beauty Academy Ltd | Leicester | 2018 |
| International Network for the Study of Spirituality | Melton Mowbray | 2011 |
| International Neurodiversity College of London Ltd | London | 2024 |
| International Nutrition and Business Academy (Inba) Ltd | London | 2023 |
| International Online Music Academy Ltd | London | 2020 |
| International Online School Limited | London | 2024 |
| International Organisation for Development | London | 2014 |
| International Organisation for Radiotherapy for Benign Conditions CIC | London | 2021 |
| International Organisation of Integrated Health Practitioners Ltd | London | 2026 |
| International Organization for Complementary and Alternative Medicine Ltd | Cardiff | 2024 |
| International Organization for Health and Nutrition Sciences Ltd | London | 2023 |
| International Organization for Quality and Sports Excellent Ltd | Luton | 2025 |
| International Organization of Creativity for Peace | Greenford | 2016 |
| International Oxford College Ltd | London | 2024 |
| International Partners York Ltd | York | 2017 |
| International Pathways Centre UK Ltd | Kington | 2025 |
| International Pathways Education Ltd | Barking | 2026 |
| International Patient Experience Academy Ltd | Kidlington | 2023 |
| International Peace Education Resources (Iper) | Portglenone | 2020 |
| International Performing Arts & Theatre Limited | London | 2010 |
| International Physical Therapy Network Ltd | London | 2025 |
| International Platform for Training and Development Ltd | Manchester | 2025 |
| International Plenitude Seminary Ltd | London | 2021 |
| International Pluto Academy Ltd | London | 2024 |
| International Positive Education Network | Ashford | 2015 |
| International PRE Schools Ltd | Cardiff | 2019 |
| International Projects Centre Limited | Exeter | 1998 |
| International PT Jacked Attire Limited | Staines-Upon-Thames | 2025 |
| International PTA Ltd. | London | 2025 |
| International Qualification Awarding Forum Ltd | London | 2024 |
| International Qualification Forum Ltd | High Wycombe | 2023 |
| International Qualifications and Awards Ltd | London | 2025 |
| International Quality Standard for Education Ltd | Ilford | 2019 |
| International Recruitment Limited | Sutton Coldfield | 2023 |
| International Responsible Leadership Ltd | Hove | 2025 |
| International Road Rescue and Trauma Consultancy Ltd. | Stoke-On-Trent | 2017 |
| International Rugby Academy New Zealand - UK Ltd | Horsham | 2025 |
| International Scholar Plus Ltd | Glasgow | 2024 |
| International Scholars Reconciliation & Revolution Corporation Limited | Ilford | 2020 |
| International School of Aesthetics Limited | Liverpool | 2024 |
| International School of Business and Technology Ltd | Birmingham | 2025 |
| International School of Canine Psychology Limited | London | 2023 |
| International School of Communication Limited | London | 2018 |
| International School of Creative Arts Limited | London | 2008 |
| International School of Intuition and Healing Ltd | London | 2024 |
| International School of London Limited | | 1991 |
| International School of Management (ISM) London Limited | Erith | 2018 |
| International School of Musicians Ltd | London | 2019 |
| International School of Nutritional Medicine Ltd | Peterborough | 2025 |
| International School of Philosophy Ltd | London | 2022 |
| International School of Psychology Limited | Brighton | 2025 |
| International School of Revenue Management Ltd | Maidstone | 2012 |
| International Schools Consultancy Services Ltd | London | 2024 |
| International Schools Consulting Limited | Telford | 2020 |
| International Schools of Business Management | London | 1977 |
| International Schools Partnership Limited | London | 2015 |
| International Science Teaching Foundation | Brighton | 2013 |
| International Scouts Volunteer Group (Isvg) Ltd | Barking | 2023 |
| International Sea Kayak Guide Alliance Ltd | Falmouth | 2023 |
| International Security Advisory Team Ltd | Alva | 2025 |
| International Security Sciences Academy (Issa) | London | 2023 |
| International Shuheng Acupuncture College Ltd | London | 2017 |
| International Shuheng Acupuncture Research Association Ltd | Carshalton | 2019 |
| International Skill Development Corporation Limited | High Wycombe | 2013 |
| International Skill Development Qualification Ltd | London | 2025 |
| International Skills & Integration Services CIC | London | 2026 |
| International Skills Academy Ltd | London | 2025 |
| International Skills Education and Career Limited | Wembley | 2023 |
| International Skincare Education (UK) Limited | Liverpool | 2025 |
| International Social Work Ltd | London | 2023 |
| International Solar Cleaning Academy Ltd | Telford | 2022 |
| International Solar Education Limited | Grimsby | 2025 |
| International Solution for Education Health and Tourism Ltd | London | 2019 |