This signals domestic refiners' efforts to take as many cargoes as possible before US sanctions against Iran come into effect in November.
According to the data released by S&P Global Platts, the 65% rise lifted Japan's imports of Iranian crude oil to 177,475 barrels per day (bpd) in August, contributing to the 5.9% year on year rise in overall crude imports to 3.39 million bpd in the month.
Imports of Iranian crude in August edged down 3.3% from July, but the Persian Gulf producer was the fifth-largest supplier to Japan in the month, accounting for 5.2% of the total volume, according to METI data.
METI publishes its data in kiloliters, which S&P Global Platts converts to barrels.
Japan's oil imports from Iran have surged since May as domestic refiners rushed to secure as many cargoes as possible before US sanctions return.
Accordingly, Japan's crude oil imports from Iran over January-August averaged 166,890 bpd, up 4.8% from a year earlier.
Japanese refiners have urged the government to seek a waiver from the US as they are keen to continue importing usual volumes of Iranian crude.
Japan remains firmly committed to seeking US exemption for Iranian oil imports as it sees the supply as important for the country's energy security and business, Ryo Minami, METI's director-general of oil, gas and mineral resources, told S&P Global Platts previously.
MR/PR