Yes, there are multiple flights from Bangkok to Yamaguchi for under ฿ 20,961. The cheapest flight booked recently is on ANA for just ฿ 19,105, but on average you can expect to pay ฿ 19,105.
There are no direct flights from Bangkok to Yamaguchi, but Cheapflights can provide you with all the information you need to find the fastest route with the fewest stops.
Airlines like ANA fly from Bangkok to Yamaguchi in about 24h 30m. The time it takes to get you to your destination can typically vary by up to .
Flying on ANA is currently your cheapest option to Yamaguchi, with prices starting at ฿ 19,105.