More than just a race, the Honolulu Marathon weekend draws in visitors and business.

This year, about 15,000 participants are from Japan. According to Jerry Agrusa, an economic expert at the University of Hawaii, roughly each participant brings along one person for the trip.

"We're looking at about 30,000 people from Japan alone. Additionally we have many people from the mainland United States, Europe and all over. The economic impact we think will approach about $140 million this year in direct spending," Jim Barahal, president and CEO, Honolulu Marathon, said. 

Agrusa says the event will generate about $5 million in direct taxes, which is great for the city. He cited a previous study by Hawaii Pacific University, the average Japanese person spends roughly $318 a day. 

"Last time we did the study, we had 1,500 surveys in Japanese. More than a quarter said that they'll go outer island. So that's good. That brings the economic significance to the outer islands," he said. 

He also says the Honolulu Marathon exposes people to Hawaii. 47 percent surveyed were from Japan in the past. 

10,000 volunteers will work on race day.