Asian imports of Iranian oil slow for first time since Jan 2016

* Asia imports 1.60 mln bpd of Iran oil in May, down 1.7 pct yr/yr

* Japan imports tumble 47.8 pct yr/yr due in part to turnaround

* Jan-May Asia imports up 30.5 pct yr/yr

TOKYO, June 30 (Reuters) - Imports of Iranian crude by its four main buyers in Asia fell 2 percent in May from a year ago, marking the first year-on-year decline since January 2016, when Western sanctions were lifted leading to a spike in Tehran's exports. Iran's top four Asian buyers - China, India, South Korea and Japan - imported 1.60 million barrels per day (bpd) last month, government and ship-tracking data showed. Iran was exempted from the Organization of the Petroleum Exporting Countries agreement to reduce output by 1.2 million bpd that began this year, a victory for Tehran which has argued it needs to regain the market share it lost under Western sanctions over its disputed nuclear program. Overall Iranian oil output was hovering at more than 3.9 million bpd and is expected to reach 4 million bpd by March 2018, Oil Minister Bijan Zanganeh said this month. Iran's oil exports to the West surged in May to their highest level since sanctions were lifted, a source familiar with Iranian oil exports said. Looking ahead, Iran's crude oil exports in July are set to fall 7 percent from this month's three-month high, mainly due to a decline in exports to Europe, a person with knowledge of the Middle Eastern country's tanker loading schedule said.

Japan's trade ministry on Friday released official data showing its Iranian imports tumbled by nearly half, reflecting lower demand because of the refinery maintenance season. The following tables show Asia's Iran crude imports in bpd for last month and the year to date.

Nation May-17 May-16 yr/yr pct China 681,762 619,300 10.1 India 487,600 379,200 28.6 Japan 160,551 307,691 -47.8 Korea 265,516 316,839 -16.2 Total 1,595,429 1,623,030 -1.7 Nation Jan-May 2017 Jan-May 2016 yr/yr pct China 600,597 565,167 6.3 India 548,200 334,100 64.1 Japan 172,974 192,181 -10.0 Korea 444,185 261,743 69.7 Total 1,765,956 1,353,191 30.5

(Reporting by Osamu Tsukimori; Editing by Christian Schmollinger)