UPDATE 1-S.Korea's oil imports from Iran fall 12 pct in March y/y

(Adds detail, background)

* March Iranian crude imports at 1.2 mln T vs 1.37 mln T y/y

* Q1 oil imports from Iran at 2.4 mln T, down 29.8 pct y/y

* Total March crude imports rise 5.8 pct y/y to 11.5 mln T

SEOUL, April 15 (Reuters) - South Korea’s oil imports from Iran fell 12 percent in March from a year earlier, customs data showed on Monday, but the monthly intake was still the highest since the country resumed buying Iranian oil in January.

South Korea, one of Iran’s biggest Asian customers, imported 1.2 million tonnes of crude oil from Iran in March, or 284,639 barrels per day (bpd), versus 1.37 million tonnes a year earlier, the data showed.

That was up 23 percent from February and more than a five-fold increase from January as buying has ramped up.

For the first three months, South Korea’s imports of Iranian crude were down 29.8 percent at 2.4 million tonnes, or 196,303 bpd, compared with 3.45 million tonnes over the same period last year, according to the data.

South Korea is one of the eight countries that received six-month waivers from the United States in November and can buy up to 200,000 bpd of oil from Iran, mostly condensate, or an ultra-light form of crude oil.

Across the five months from November through March, South Korea imported about 117,000 bpd on average of Iranian oil, according to Reuters calculation based on the customs data.

The sanctions waiver is due to expire in early May and South Korea has been in talks with the United States to extend its waiver to continue to source oil from Iran.

The U.S. goal is to reduce the number of sanctions waivers and to cut Iran’s oil exports about 20 percent, to below 1 million barrels of oil per day from May, sources have said.

In total, South Korea’s March crude oil imports were 11.5 million tonnes, or 2.72 million bpd, up 5.8 percent from 10.9 million tonnes a year earlier.

Oil shipments from the United States were more than seven times higher in March at 1 million tonnes, from 134,911 tonnes a year earlier, according to the data.

Imports from Saudi Arabia, the country’s top crude oil supplier, fell 9.5 percent to 2.7 million tonnes, from a year earlier, the data showed.

For the first quarter of the year, crude oil imports increased 1.2 percent to about 37.2 million tonnes year-on-year.

The country’s final crude oil imports data will be released later this month from state-run Korea National Oil Corp (KNOC). (Reporting By Jane Chung; editing by Richard Pullin)