China, India, Japan and South Korea last month imported a total of 1.63 million barrels per day (bpd) from Iran, the lowest volume since December, the data showed.
Iran has been pushing to retain its prized customers in Asia but concerns that US President Donald Trump will carry out a threat to exit Tehran's nuclear deal with world powers and re-impose sanctions has dampened appetite for the country's crude, amid a persistent global glut.
China's February imports of Iranian crude tumbled nearly 28 percent from the previous year to a 13-month low of 474,386 bpd. The country's overall crude imports rose by 1.5 percent last month.
India's imports from Iran rose 1.3 percent to 655,500 bpd last month. Korea's purchases were down almost a third.
Imports into Japan were down about 22 percent from a year earlier at 180,144 bpd, marking the 10th straight monthly decline, data from the country's Ministry of Economy, Trade and Industry showed on Friday.