China has identified the only three bodies recovered from the sunken NITC suezmax Sanchi.
All 32 seafarers lost their lives when the vessel caught fire following a collision off Shanghai on 6 January.
Iran's ISNA news agency said the three men were identified as Milad Aravi, Majid Naqian and Mohammad Kavousi, all Iranian.
The Iranian government is trying to repatriate the bodies.
The vessel was heading from Iran to South Korea with 136,000 tonnes of condensate worth around $60m.
It sank on 14 January, but not before rescue workers had found the three bodies.
The crew consisted of 30 Iranians and two Bangladeshis.
The black box from the vessel and the CoscoCS bulker involved in the collision have now been opened.
Maritime authorities in China, Panama, Iran and Hong Kong have reached a deal to jointly investigate the collision.