Dr Kashin  a Russian defense expert, wrote in Sputnik News [article of Dec/09/2015, https://jp.sputniknews.com/japan/20151209/1290996.html in Japanese] that submarine technology transfer from Japan to Taiwan is highly unlikely. If you right-click mouse to translate Kashin's article you will see he said, along the lines:
Only the US can challenge China by anticipating the Submarine Project of Taiwan. The US could obviously assist Taiwan in a joint project on combat and sonar systems. But, issues on the energy system and structural elements, which are diesel submarine specific, are difficult to solve. Also, in the US, there are very strong opponents against introduction of non-nuclear submarines. The opponents have blocked any investment or technological development for manufacturing non-nuclear submarines.
As Japan has many problems with China, the Japanese government will never make a decision which triggers a harsh, long-term, confrontation with the Chinese government.
An indigenous Taiwanese submarine development and building project, if it drew from foreign technology, could possibly be implemented. If the US participated in the project as a major partner of Taiwan, the US would herself, draw huge criticism from the Chinese government. Possible partners with Taiwan, excluding Japan are France, Germany, Sweden, etc.
Japanese submarines are too big for Taiwan. However, if a contract with Taiwan were drawn up [by any assisting countries] it would be kept very secret.
 Dr. Vassily Kashin has a Ph.D. in Political Science, is a senior research fellow at the Center for Comprehensive European and International Studies at the National Research University [one of Russia's top universities] - Higher School of Economics. He is also a leading research fellow at the Institute of the Russian Far East.
Anonymous & Pete