| Innovate FD Ltd | Professional & scientific | 2021 |
| Innovate Surrey Ltd | Education | 2021 |
| Innovate-Is Limited | Professional & scientific | 2016 |
| Innovateer Limited | Professional & scientific | 2016 |
| Innovation Electrical Ltd | Extraterritorial | 2025 |
| Innovation Techno Limited | Information & communication | 2025 |
| Innovfocus Ltd | Administrative & support | 2021 |
| Inside OUT Retreats Limited | Health & social care | 2005 |
| Insideout Creative Limited | Administrative & support | 2006 |
| Insight Dojo Limited | Professional & scientific | 2013 |
| Insight for Living (UK) Limited | Other services | 2006 |
| Insight Traction Consulting Ltd | Professional & scientific | 2026 |
| Insight Traction Limited | Professional & scientific | 2012 |
| Insight Traction Partners Limited | Professional & scientific | 2026 |
| Inspark Ltd | Information & communication | 2017 |
| Inspiral Software Limited | Information & communication | 2010 |
| Inspire Development Ltd | Professional & scientific | 2003 |
| Inspired Gardens (Guildford) Limited | Other services | 2014 |
| Inspired Styling Ltd | Other services | 2023 |
| Instinct Music Ltd | Information & communication | 2018 |
| Insure Recruitment Limited | Administrative & support | 2012 |
| Intakelogic Ltd | Information & communication | 2025 |
| INTEGR8AI Human Technologies Ltd | Information & communication | 2024 |
| Integra Carpentry Ltd | Manufacturing | 2021 |
| Integration Intelligence Ltd | Professional & scientific | 2026 |
| Integrity Commercial Cleaning Ltd. | Other services | 2013 |
| Integrity E-Commerce Ltd | Wholesale & retail | 2021 |
| Integrity Fire Limited | Construction | 2018 |
| Integrity Property and Lettings Limited | Real estate | 2021 |
| Intellectual Property Limited | Administrative & support | 2025 |
| Intellectus Group Ltd | Public administration | 2019 |
| Intelligent Life Limited | Professional & scientific | 2016 |
| Inter-Planetary Link Ship Limited | Professional & scientific | 2026 |
| Intercai Limited | Information & communication | 2025 |
| Intercai Mondiale Limited | Professional & scientific | 1996 |
| Interface Property Services Limited | Construction | 1995 |
| Interlets Limited | Real estate | 2005 |
| International Dragon Boat Federation Limited | Education | 2020 |
| International Hair Studio (Guildford) Ltd | Other services | 2026 |
| Intervals Ltd | Wholesale & retail | 2023 |
| Interweb Media Limited | Information & communication | 1999 |
| Into the Fold London Limited | Administrative & support | 2016 |
| Intouch Developers Ltd | Information & communication | 2024 |
| Inuvika Limited | Information & communication | 2014 |
| INV Group Holdings Limited | Financial services | 2017 |
| Invani Cycling Clothing Ltd | Wholesale & retail | 2016 |
| Invariant Capital Limited | Professional & scientific | 2026 |
| Invcreative Limited | Professional & scientific | 2024 |
| Invdev Limited | Information & communication | 2022 |
| Inventurez Limited | Administrative & support | 2011 |
| Inverifi Limited | Information & communication | 2020 |
| Investlist Limited | Extraterritorial | 2024 |
| Invictus Construction Ltd | Other services | 2017 |
| Invoke Art Ltd | Wholesale & retail | 2025 |
| Invotra Limited | Information & communication | 2020 |
| Invotra Shared Services Limited | Information & communication | 2009 |
| Invuse Limited | Information & communication | 2019 |
| IO1 Limited | Information & communication | 2004 |
| Ionian Weddings Ltd | Administrative & support | 2007 |
| Iotech Engine Limited | Information & communication | 2016 |
| IP Equipment Sales Ltd. | Wholesale & retail | 1992 |
| Ireland Group Advisory Ltd | Professional & scientific | 2022 |
| Iroguildford Ltd | Real estate | 2026 |
| Iron Culture Clothing Ltd | Wholesale & retail | 2021 |
| Iron Hawk Security Ltd | Administrative & support | 2023 |
| Irons Storage Solutions Ltd | Transport & logistics | 2021 |
| Ironstone Energy Limited | Energy | 2022 |
| Isaac Bell Ltd | Arts & recreation | 2019 |
| Isabel Perez Major Consultancy Limited | Professional & scientific | 2020 |
| ISG (Group Services) Limited | Administrative & support | 1983 |
| Island Cottage Rentals Limited | Real estate | 2024 |
| Ismax Limited | Construction | 2014 |
| Isobi Royai Consult Limited | Administrative & support | 2021 |
| Ispo Impact Foundation Limited | Other services | 2026 |
| Ispo Sports Business Events Ltd | Administrative & support | 2025 |
| IT Financial Services Ltd | Construction | 2011 |
| IT PER4MANCE Limited | Information & communication | 2016 |
| IT Tamed Limited | Information & communication | 2025 |
| IT365 Limited | Information & communication | 2024 |
| Italian Kitchen at Festivals Ltd | Hospitality | 2015 |
| ITC Consult Ltd | Professional & scientific | 2024 |
| ITK Services Ltd | Information & communication | 1994 |
| ITR Meat Production Limited | Manufacturing | 2025 |
| Itsabook Limited | Education | 2015 |
| IV Bar Limited | Other services | 2023 |
| Ivator Investments Limited | Real estate | 1973 |
| IVE1.DDD Ltd | Administrative & support | 2020 |
| Ivey Scott Music Ltd | Education | 2012 |
| IVF Solutions Limited | Information & communication | 2012 |
| Ivor Heath Limited | Households | 1999 |
| IVY Education Ltd | Administrative & support | 2010 |
| IVY Lane Property Investments Ltd | Real estate | 2024 |
| Ivybank (Godalming) Residents Association Limited | Professional & scientific | 1985 |
| IYT Limited | Real estate | 2012 |
| IZ Connect Limited | Energy | 2019 |
| J & B Food & Wine Limited | Wholesale & retail | 2026 |
| J & G Traffic Ltd | Construction | 2015 |
| J & L Care Services Limited | Health & social care | 2023 |
| J and a Real Estate Limited | Real estate | 2018 |
| J D Beastall Ltd | Construction | 2022 |