TOKYO -- Airfares from Japan to South Korea's capital are in free fall along with bilateral relations, with one-way fares from smaller Japanese cities as cheap as 1,000 yen ($9.35) before taxes and fuel surcharges.

According to Airplus, operator of the Ena budget ticket site, one-way tickets this month are as low as 1,000 yen from Fukuoka and Ibaraki to Seoul, and 1,500 yen from major hubs Kansai International Airport and Narita International Airport -- roughly 60% to 80% less than a year ago.

Once fuel surcharges and taxes are included, round trips to the South Korean capital can be had for as little as 8,000 to 12,000 yen. These are largely weekday flights on budget carriers.

Last year, the cheap fares were around 13,000 to 18,000 yen. "September is the busy season, so fares this low around now are really exceptional," a source at the site operator said.

September round-trip fares of 23,000 to 24,000 yen can be found on Japanese travel site AirTrip -- roughly 20% to 30% less than a year earlier.

South Korea's Chuseok holidays in mid-September usually result in a rush of tourists to Japan. But "this year, reservations are down 80%," said an official at the Japanese branch of South Korean tour operator Modetour Network.

Arrivals in South Korea by Japanese visitors increased 19.2% on the year for July, according to the Korea Tourism Organization -- up for the 17th time in a row.

But visitors from South Korea to Japan declined 7.6% for July and apparently fell sharply in August.

In response, such large South Korean carriers as Korean Air Lines and Asiana Airlines have reduced or suspended service to Japanese destinations.