No Guarantee that More Japan-Linked Vessels will be able to Pass through Strait of Hormuz

By Sho Komine / Yomiuri Shimbun Staff Writer

14:16 JST, April 10, 2026

Three Japan-linked vessels have been able to pass through the Persian Gulf since Iran effectively blockaded the Strait of Hormuz, but there is no guarantee that more Japan-flagged ships will be permitted to do so.

All three vessels have connections with either Oman or India and were bound for one of those two countries, both of which maintain friendly relations with Iran.

Iran may have permitted the vessels to pass through the strait based on their connections with Oman and India rather than with Japan, according to an expert.

The Japanese government defines a Japan-linked vessel as one that meets any of the following criteria: it is registered under the Japanese flag; it has Japanese crew members on board; it is operated by a Japanese company; or its cargo is destined for Japan.

At the start of the blockade, 45 vessels operated by member companies of the Japanese Shipowners’ Association were either sailing through or docked in the Persian Gulf.

The first Japan-linked vessel to pass through the strait was a liquefied natural gas carrier jointly owned and operated by Mitsui O.S.K. Lines, Ltd. and an Omani state-owned company.

Analysis of the vessel’s position data showed it passed through Omani territorial waters on the southern side of the strait on April 2 and headed for a port in Oman.

Oman has been holding high-level talks with Iran following the blockade to ensure smooth passage.

The second and third Japan-linked ships were liquefied petroleum gas carriers owned and operated by an Indian affiliate of Mitsui O.S.K. Lines. They passed through the route north of the strait, which is controlled by Iran, on April 3 and 5 and headed for India.

When passing through the strait, the second and third vessels transmitted information identifying themselves as Indian ships with Indian crews. After the ships passed through, it was confirmed that they were escorted by Indian Navy vessels.

The Indian government has previously explained that India-linked vessels were able to pass through the strait as a result of negotiations with Iran.

Koichiro Tanaka, professor of Iranian politics at Keio University, said: “Iran still holds the power to decide which vessels can pass. That has not changed. It cannot be definitively said that the three vessels were able to pass simply because they were related to Japan. There is no sign that other Japan-linked vessels still in the gulf will be able to pass.”