| Hood Property Saltcoats Ltd | Real estate | 2021 |
| Hood Xiii Limited | Other services | 2025 |
| HOP on Productions Limited | Information & communication | 2013 |
| Hope Vending Ltd | Wholesale & retail | 2022 |
| House of Scots Limited | Wholesale & retail | 2025 |
| Houses to Rent Ayrshire Limited | Real estate | 2022 |
| Houston’S Homes Ltd | Construction | 2024 |
| Howie Project Services Ltd | Professional & scientific | 2026 |
| Howrob Investments Ltd | Households | 2025 |
| HRM Group Holdings Ltd | Financial services | 2025 |
| HRM Homecare Services Ltd. | Health & social care | 1996 |
| HSA Retail Limited | Real estate | 2017 |
| HSA Retail Partners Ltd | Professional & scientific | 2017 |
| HSC Futures Ltd | Administrative & support | 2005 |
| Hunter Conservatories & Sunrooms Limited | Construction | 2018 |
| Hunter Group (Scotland) Limited | Mining & quarrying | 2009 |
| Hunter Mining (Offshore) Limited | Mining & quarrying | 2012 |
| Hunter Pipeline Solutions Ltd | Manufacturing | 2025 |
| Hurlford Grocers Limited | Wholesale & retail | 2025 |
| Hurlford Top One Limited | Hospitality | 2026 |
| Hustle Salon Ltd | Other services | 2025 |
| Hutchinson People Management Consultants Ltd. | Professional & scientific | 2025 |
| Hydro Flow Drainage and Civils Limited | Construction | 2024 |
| Hyslop Heating and Plumbing Solutions Limited | Construction | 2025 |
| I FIX Stuff Ltd | Construction | 2023 |
| I Wheelz Ayrshire Ltd | Wholesale & retail | 2016 |
| I Wheelz Scotland Ltd | Wholesale & retail | 2022 |
| I.D Bathrooms Ltd | Wholesale & retail | 2024 |
| I.H. Borland (Contractors) Limited | Construction | 1996 |
| IAN Hinde Plumbing & Heating Ltd | Construction | 2020 |
| Ibest UK Ltd | Wholesale & retail | 2017 |
| IC Coaching Ltd | Health & social care | 2025 |
| Icas+ Ltd | Construction | 2019 |
| Icon 9 Ltd | Administrative & support | 2021 |
| ICS Ayrshire Limited | Professional & scientific | 2018 |
| Ideal Finance Solutions Ltd | Professional & scientific | 2025 |
| IDM Property Ltd | Real estate | 2023 |
| IDS + Co Ltd | Professional & scientific | 2012 |
| Ignite Advertising Ltd. | Professional & scientific | 2024 |
| IHH Solutions Limited | Real estate | 2022 |
| IM Joinery Limited | Construction | 2021 |
| Imagine Build Race Ltd | Wholesale & retail | 2025 |
| Imps Claims Ltd | Other services | 2025 |
| IN the MIX Limited | Wholesale & retail | 2010 |
| Inari Investments Limited | Wholesale & retail | 2021 |
| Indal Properties Ltd | Construction | 2025 |
| Independence-Uk Ltd | Professional & scientific | 2015 |
| Indigo Black Consulting Ltd | Professional & scientific | 2018 |
| Indoor Market Retail Ltd | Wholesale & retail | 2024 |
| Industrial and Power Association Limited | Professional & scientific | 1992 |
| Infab Limited | Financial services | 2010 |
| INFIN8TY Consulting Ltd | Professional & scientific | 2025 |
| Informology Limited | Information & communication | 2004 |
| Inglenook Property Limited | Construction | 2018 |
| Inglenook Property Rental Ltd | Extraterritorial | 2021 |
| Ingyne Ltd. | Arts & recreation | 2008 |
| Innis Ness Ltd | Education | 2024 |
| Innovative Space Solutions Ltd | Real estate | 2014 |
| Innovec Limited | Professional & scientific | 2010 |
| Inspired Modern Living Ltd | Wholesale & retail | 2026 |
| Integrated Access Services Ltd | Construction | 2023 |
| Integrated Engineering Consultants Ltd | Construction | 2023 |
| Intellect Tech Ltd | Professional & scientific | 2021 |
| Intl CIC | Professional & scientific | 2020 |
| Inverallan Property Limited | Real estate | 2026 |
| Invershaw Limited | Administrative & support | 2012 |
| IO Kurdish Ltd | Hospitality | 2024 |
| Iolaire Media Ltd. | Professional & scientific | 2003 |
| IP Support Services Limited | Administrative & support | 2019 |
| IPR Drilling Limited | Real estate | 2005 |
| IPR Drilling Services UK Limited | Construction | 2008 |
| Ipsilon Consultancy Ltd | Professional & scientific | 2006 |
| Ironside Facilities Solutions Ltd | Administrative & support | 2026 |
| Ironworx Property Ltd | Real estate | 2025 |
| Ishr Properties Ltd | Real estate | 2023 |
| It's GOT 2 B Real Limited | Real estate | 2022 |
| J & C Property Development Services Ltd | Real estate | 2020 |
| J & J Property Development Services Ltd | Real estate | 2020 |
| J & M Sommerville Ltd | Wholesale & retail | 2018 |
| J & S Amusements Limited | Extraterritorial | 2022 |
| J & S Apartments Limited | Real estate | 2024 |
| J & S Autos (Glasgow) Ltd. | Wholesale & retail | 2010 |
| J & S Bingo Limited | Hospitality | 2014 |
| J & W Carpets Limited | Wholesale & retail | 2009 |
| J and B Contracts (Ayrshire) Ltd | Construction | 2014 |
| J Banks Rail Services Ltd | Construction | 2020 |
| J Hannah Enterprises Ltd | Professional & scientific | 2016 |
| J Wilson Engineering Services Ltd | Professional & scientific | 2023 |
| J&J Property (Scot) Ltd | Real estate | 2025 |
| J&S Motors (Ayrshire) Limited | Wholesale & retail | 2013 |
| J. S. Geddes Design Partnership Limited | Wholesale & retail | 2000 |
| J.C.S. Storage Limited | Transport & logistics | 2004 |
| J.G. Douglas Financial Services Limited | Professional & scientific | 2012 |
| J.N.S. Landscapes and Maintenance Limited | Administrative & support | 2019 |
| Jacob Consultant 4 Ltd | Administrative & support | 2024 |
| Jada Holdings Ltd | Real estate | 2021 |
| Jade Kilma Ltd | Hospitality | 2025 |
| Jaimac Design Ltd | Administrative & support | 2013 |
| JAM Street Dance Centre CIC | Hospitality | 2023 |
| James Brown (Kilmarnock) Limited | Real estate | 1954 |