Koudai Maru and Hyōjin Maru are fishing charter boats based at Sakihario Fishing Port in Sasebo, Nagasaki, offering sea-fishing trips in the waters around the Goto Islands and Goto-nada. The operators welcome beginners, families and experienced anglers, with the captain providing support and choosing fishing locations to suit the season. Trips target a wide variety of fish, including red sea bream, rockfish, amberjack, yellowtail and swordtip squid.

Guests can choose introductory trips for tai-rubber or mixed reef fishing, more advanced jigging and casting outings, or night squid-fishing trips. Both shared and private charter options are available, and fishing-gear rentals are offered; bait and tackle can also be purchased. The boats are equipped with fish finders, GPS, radar, a flush toilet and a rest area, with a flat deck designed to make fishing comfortable, including for newcomers and families with children. In addition to fishing, the business offers sightseeing cruises around Huis Ten Bosch and Saikai Bridge. Safety is a priority, and departures are not made when conditions are unsuitable.