| Herbert & Sons Limited | Extraterritorial | 2002 |
| Herbert Group Limited | Financial services | 1997 |
| Herbert Trustee Limited | Extraterritorial | 1998 |
| Here BE Giants Limited | Information & communication | 2024 |
| Heronlea Ltd | Financial services | 2001 |
| Herrings Restaurants Limited | | 1990 |
| Hexalogica Ltd | Information & communication | 2023 |
| Heywoods Grange Limited | Health & social care | 1996 |
| HFM Capital Limited | Professional & scientific | 2024 |
| Hickman Supplies Limited | Wholesale & retail | 2002 |
| Hidden Stag Games Ltd | Information & communication | 2021 |
| Hiedra Marketing Ltd | Professional & scientific | 2022 |
| High Definition Ventures Ltd | Other services | 2023 |
| High Lodge Shooting School Leisure Limited | Manufacturing | 2004 |
| Highgrove Resources Limited | Construction | 2002 |
| HIH Assessments Ltd | Professional & scientific | 2007 |
| Hillcote Property Management Limited | Households | 1998 |
| Hispalingua Ltd | Information & communication | 2026 |
| Historic Suffolk Ltd | Arts & recreation | 1973 |
| HJ Boutique Limited | Manufacturing | 2024 |
| HJR Development Limited | Construction | 2015 |
| Hkers in Soton CIC | Wholesale & retail | 2023 |
| Hlntv Limited | Professional & scientific | 2024 |
| Hmbkd Ltd | Wholesale & retail | 2021 |
| Hmkt Limited | Real estate | 2004 |
| HNE (UK) Biotechnology Co Ltd | Wholesale & retail | 2026 |
| Hobby-G Ltd | Wholesale & retail | 2024 |
| Holly House Residents Association (EYE) Limited | Hospitality | 1974 |
| Holmes Travel Limited | Administrative & support | 1981 |
| Holocaust Memorial Day Trust | Administrative & support | 2005 |
| Homebridge Properties Ltd | Real estate | 2023 |
| Homeland School of Intelligence and Investigation Studies Limited | Education | 2024 |
| Honest&Flourish International Logistics Co., Ltd | Extraterritorial | 2013 |
| Honof Homes Limited | Extraterritorial | 2023 |
| Horse Requisites Newmarket Limited | Wholesale & retail | 1972 |
| Horsley Holder Properties Limited | Real estate | 1973 |
| Hospice Trading (Ipswich) Limited | Wholesale & retail | 1989 |
| Hostseo Limited | Information & communication | 2019 |
| Hot WOK Ltd | Hospitality | 2017 |
| House Life Ltd | Construction | 2018 |
| Housing & Property Services Limited | Real estate | 2024 |
| Howe Enterprises (Car Clinic) Ltd | Wholesale & retail | 2025 |
| HPB Management Limited | Financial services | 1981 |
| Hutchinson Investment Corporation Limited | Extraterritorial | 2000 |
| Hyde Parker Farms Limited Partnership | | 1995 |
| HZ Medical Limited | Health & social care | 2023 |
| IAN Davison Limited | Information & communication | 2012 |
| IAN Dicker Camera Crew Ltd | Information & communication | 2002 |
| Ibrahim's Innovations Ltd | Wholesale & retail | 2020 |
| Ican Data Solutions Limited | Information & communication | 2018 |
| Icsys Consultancy Ltd | Information & communication | 2024 |
| IG World Logistics Ltd | Transport & logistics | 2024 |
| IG Autoworld Ltd | Wholesale & retail | 2024 |
| Iheartblob Ltd | Arts & recreation | 2019 |
| Iiegroup Ltd | Information & communication | 2020 |
| Imaani Group Ltd | Wholesale & retail | 2024 |
| Imaxmt Importand Export Co., Limited | Wholesale & retail | 2024 |
| Inc'D Ltd | Administrative & support | 2026 |
| Infinity 8 Hasc Ltd | Health & social care | 2022 |
| Inform Furniture Limited | Wholesale & retail | 2000 |
| Ingland Ltd | Information & communication | 2024 |
| Inixdev Ltd | Information & communication | 2023 |
| Injury Lawyers UK Ltd | Professional & scientific | 2008 |
| INNOV8TIVE Technologies Ltd | Information & communication | 2024 |
| Innovative Mechatronic Systems Integrators Ltd | Construction | 2021 |
| Inovatel Limited | Information & communication | 2003 |
| Inspired Networks Limited | Information & communication | 1998 |
| Inspired Property Developers Limited | Real estate | 2026 |
| Instarry Limited | Information & communication | 2023 |
| Insurelink (East Anglia) Limited | Financial services | 1995 |
| Inteck Automation Limited | Manufacturing | 1995 |
| Inteck Holdings Limited | Manufacturing | 1985 |
| Integrated Construction Technologies Limited | Construction | 2023 |
| Integrated Labs Limited | Professional & scientific | 2020 |
| Intelligent Booking Ltd | Extraterritorial | 2017 |
| Interaction Interactive Ltd | Information & communication | 2021 |
| International Flavours & Fragrances (CIL) Limited | Manufacturing | 1996 |
| International Flavours & Fragrances (GB) Holdings Limited | Professional & scientific | 2000 |
| International Flavours & Fragrances I.F.F.(Great Britain)Limited | Manufacturing | 1926 |
| International Union of Neuro Linguistic Programming (Iunlp) Ltd | Administrative & support | 2020 |
| Inventa UK Group Ltd | Administrative & support | 2025 |
| Iolair (UK) Limited | Professional & scientific | 1995 |
| Ipswich and Suffolk Bangladeshi Muslim Community Centre and Mosque | Education | 2001 |
| Ipswich Buses Limited | Transport & logistics | 1986 |
| Ipswich Hydraulic Systems Limited | Manufacturing | 2003 |
| Ipswich Private Kindergarten Limited | Other services | 2001 |
| Ireland Brothers Trucking Limited | Transport & logistics | 2012 |
| Ironshield Cyber Ltd | Wholesale & retail | 2025 |
| Ironside Enterprises Limited | Real estate | 1999 |
| Ironwill Trading Ltd | Wholesale & retail | 2024 |
| Ishaft Systems UK Ltd | Information & communication | 2023 |
| Isles Health Limited | Wholesale & retail | 2021 |
| Israel Vicente Chemical Group Co., Ltd | Mining & quarrying | 2025 |
| ITJ Products Ltd | Manufacturing | 2022 |
| Ivan Byelskyy Limited | Transport & logistics | 2019 |
| IVD Certify Limited | Financial services | 2024 |
| Iwkua Ltd | Information & communication | 2020 |
| Ixworth Medical Services Limited | Wholesale & retail | 2005 |
| Izabelallnacampetellastore Ltd | Wholesale & retail | 2025 |
| J & J Howlett (Investments) Limited | Real estate | 2002 |