Following the reporting of a company whistleblower in February 2024, on April 24, 2024, the company announced that investigation was underway by the Ministry of Land, Infrastructure, Transport and Tourism of its subsidiary, IHI Power Systems Co., which had falsified its engine data since 2003, affecting over 4,000 engines worldwide.

IHI develops, manufactures, and maintains aero engines, either by joint projects of which partners include GE Aviation, Pratt & Whitney, and Rolls-Royce Holdings, or the company itself.

It remains part of IHI's business activities, although it has been diluted through several mergers with other Japanese shipbuilding companies.

In 2013, IHI Marine United was merged with Universal Shipbuilding Corporation owned by the steel company JFE Holdings in order to newly establish a larger firm, Japan Marine United Corporation (JMU), of which IHI remained a shareholder.

In March 2020, Japan Marine United (with 49% of shares) agreed to merge with Imabari Shipbuilding (with 51% of shares) into a joint venture named Nihon Shipyard (NSY), covering all ship types except Liquefied natural gas (LNG) tankers.