The Japanese Ministry of Economy, Trade and Industrys data show that the Asian countrys crude oil imports from Iran in September rose 35 percent compared to the same month last year.
According to the figures released by the ministry, the imports surged to 252,216 barrels per day (bpd), Reuters reported Thursday.
Japan, China, India and South Korea are among the main importers of Irans crude exports, which they need to meet their energy demands.
Irans crude importers are under pressure from the West to cut their purchases from the country under the illegal Western sanctions on Tehran over its nuclear energy program.
The United States, Israel and some of their allies have repeatedly accused Tehran of pursuing non-civilian objectives in its nuclear energy program, with the US and European Union using the claim as an excuse to impose illegal sanctions against Irans oil and financial sectors.
Iran has categorically rejected the allegation, stressing that as a member of the International Atomic Energy Agency (IAEA) and a signatory to the Non-Proliferation Treaty (NPT), it is entitled to develop nuclear technology for peaceful purposes.