South Korean President Lee Myung-bak called for safety measures to minimize damage from the storm that forecasters said had the potential to become the most devastating in a decade.
It was expected to pack sustained winds of 69 mph and gusts of 86 mph at its center when it hit the coast. The category 1-equivalent storm could drop 10- to 12 inches of rain.
The storm, which is more than 900 miles wide, passed over Okinawa Sunday, Stars and Stripes reported.
Rain squalls along with winds of 38 mph gusting to 50 mph were expected to continue on the island until at least Monday night and possibly into Tuesday morning.
Bolaven lashed Okinawa Sunday, with winds as high as 161 mph, making it the strongest storm to hit the area in 50 years, CNN reported.
"It's been very, very severe," said storm chaser James Reynolds, who was on the northwestern coast of the island during the worst of it.
Japanese media reports said as many as 75,000 households had been hit by power outages in 12 cities in Okinawa and Kagoshima prefectures.
The official Chinese news agency Xinhua quoted Japan's public broadcaster Nippon Hoso Kyokai as saying the local utility was trying to assess the damage but was hampered by high winds.
Xinhua said more than 5,500 people on the Amami Islands had been advised Monday by local governments to evacuate due to threats of landslides or mudflows triggered by the typhoon.
The storm also disrupted public transportation and several morning flights were canceled at local airports.
"The eye of the typhoon actually crashed ashore just after dark. ... Like the rest of the population we all just kind of holed up in the strong and sturdy buildings, which make up Okinawa," Reynolds told CNN.
While Bolaven was more than 800 miles from the second typhoon, Tembin, forecasters in Taiwan said that was close enough for Bolaven to reverse the second storm's course and push it back toward the island nation, the Taipei Times reported.
Tembin first came ashore at Hengchun Friday where it spent 2 1/2 hours before moving back out to sea and downgrading to a tropical storm. However, it regained strength and its typhoon status Sunday.
It is forecast to make landfall for a second time on the Hengchun Peninsula Monday night or Tuesday morning.
In its first venture over Taiwan, Tembin caused more than $4 million in crop damage, agriculture officials said.
The Taiwanese military has helped evacuate 4,500 residents in recent days and removed five tons of mud from streets.
In 2002, Typhoon Rusa struck South Korea, killing at least 246 people and inflicting about $5.5 billion of damage.