| I4HOUSING Ltd | Information & communication | 2016 |
| IAI Properties Limited | Real estate | 2017 |
| Iam:Brands Ltd | Professional & scientific | 2019 |
| IAN Gascoigne Limited | Construction | 2014 |
| IAN Saunders Limited | Information & communication | 2016 |
| IBA Corporate Brokers Limited | Administrative & support | 2020 |
| IBA Corporate Limited | Administrative & support | 2018 |
| IBA Corporate Sales Limited | Administrative & support | 2020 |
| IC Capital Ltd | Construction | 2011 |
| IC Wealth Financial Planning Ltd | Financial services | 2012 |
| Iceberg Developments Limited | Construction | 2018 |
| Ichigo Ichie Consulting Services Limited | Hospitality | 2017 |
| ICI Caldaie Limited | Professional & scientific | 2003 |
| Icon NDT Ltd | Professional & scientific | 2020 |
| Iconic Seating Limited | Manufacturing | 2021 |
| ID Carpentry & Joinery Ltd | Construction | 2024 |
| IDA Treasurehunter Ltd | Professional & scientific | 2018 |
| Idatamaze Limited | Information & communication | 2021 |
| Idcr Associates Limited | Professional & scientific | 2013 |
| Ideal Edge Limited | Information & communication | 2025 |
| Ideal Project Services Limited | Information & communication | 2026 |
| Identify Direct Ltd | Wholesale & retail | 1998 |
| Iedutainments Limited | Information & communication | 2010 |
| IFA Consulting Limited | Professional & scientific | 2023 |
| Iflex Health Ltd | Health & social care | 2016 |
| Ifnms Limited | Administrative & support | 2008 |
| Ignimbrite Limited | Professional & scientific | 2018 |
| Ignite AI Partners Limited | Professional & scientific | 2024 |
| Ignite Coaching & Consulting Limited | Professional & scientific | 2019 |
| Iiszon Limited | Administrative & support | 2024 |
| IKB Developments Limited | Construction | 2018 |
| Iliedanila Ltd | Hospitality | 2025 |
| Illuminated Beauty Leamington Limited | Other services | 2022 |
| Im&B Services Ltd | Information & communication | 2021 |
| Imaginate Creative Limited | Information & communication | 2003 |
| Imaging Matters Limited | Professional & scientific | 2016 |
| Immediate Machining Services Limited | Professional & scientific | 2012 |
| Immy's Web Studio Ltd | Wholesale & retail | 2021 |
| Impact Intelligence Limited | Professional & scientific | 2019 |
| Impact IRL Limited | Professional & scientific | 2025 |
| Impact ME Global Limited | Education | 2019 |
| Imperial Healthcare and Support Ltd | Administrative & support | 2022 |
| Impirius Group Limited | Other services | 2017 |
| Impirius Limited | Information & communication | 2002 |
| Imrge Ltd | Information & communication | 2016 |
| Imrie Design Limited | Professional & scientific | 2025 |
| IN Easy Steps Limited | Information & communication | 2002 |
| IN Partnership Retail Limited | Professional & scientific | 2009 |
| IN2 Apps Ltd | Extraterritorial | 2012 |
| IN2CULTURES Ltd | Education | 2011 |
| INA Medical Massage Ltd | Other services | 2022 |
| Incellacon Global Limited | Administrative & support | 2024 |
| Independent Drinks Supplies Limited | Wholesale & retail | 2005 |
| Independent Fire Engineering Services Limited | Professional & scientific | 2010 |
| Independent Groundworks Supplies Limited | Wholesale & retail | 2017 |
| Independent Resource Services (UK) Limited | Administrative & support | 2012 |
| Indigo Brain Ltd | Extraterritorial | 2011 |
| Indigo Hair Ltd | Other services | 2006 |
| Indigo Infrastructure Services Limited | Professional & scientific | 2010 |
| Indigonirvana Ltd | Information & communication | 2017 |
| Individual Property Solutions Limited | Professional & scientific | 2005 |
| Indulgence Foods Limited | Manufacturing | 2012 |
| Indulgence Patisserie Limited | Manufacturing | 2015 |
| Industrial Management Specialists(I.M.S)Limited | Professional & scientific | 1970 |
| Industrial Products Online Limited | Wholesale & retail | 2012 |
| Industrial Steel & Cladding Limited | Construction | 1998 |
| Indyleam Ltd | Other services | 2020 |
| Ineltek Ltd | Administrative & support | 2009 |
| Infinite Pixel Limited | Information & communication | 2015 |
| Infinite Service Group Ltd | Health & social care | 2026 |
| Infinity Dogs CIC | Education | 2023 |
| Infinity Group Trading Company Limited | Financial services | 2018 |
| Inform Recruitment Ltd | Administrative & support | 2021 |
| Information Management Solutions Limited | Extraterritorial | 2009 |
| Information Risk Consultants Limited | Information & communication | 2021 |
| Infour Properties Limited | Professional & scientific | 2018 |
| Ingenioso Consulting Limited | Professional & scientific | 2015 |
| Inkado Limited | Professional & scientific | 2024 |
| Inn Express Limited | Administrative & support | 2001 |
| Inn Express Properties Limited | Extraterritorial | 2023 |
| Inner Circle Legal Limited | Professional & scientific | 2025 |
| Inner Leader Limited | Professional & scientific | 2014 |
| Innocent Group Limited | Professional & scientific | 2019 |
| Innocent Group Portfolio Ltd | Real estate | 2024 |
| Innoteq Ltd | Wholesale & retail | 2021 |
| Innova Management Services Limited | Professional & scientific | 2016 |
| Innovatetechx Ltd | Information & communication | 2024 |
| Innovation POD Ltd | Education | 2019 |
| Innovergy UK Limited | Energy | 2023 |
| Innoveritas Ltd | Information & communication | 2023 |
| Insert Title Here Productions Ltd | Wholesale & retail | 2024 |
| Inside and OUT Maintenance Cleaning Limited | Administrative & support | 2021 |
| Inside OUT Theatre Company Limited | Arts & recreation | 1988 |
| Insight Capital & Advisory Ltd | Professional & scientific | 2005 |
| Insight Driven Marketing Limited | Professional & scientific | 2011 |
| Insight Nugget Ltd | Information & communication | 2020 |
| Insight on Foods Limited | Professional & scientific | 2013 |
| Insight Pathfinders Ltd | Professional & scientific | 2012 |
| Inspection Tech Limited | Professional & scientific | 2020 |
| Inspection Technologies Ltd | Professional & scientific | 2009 |