China handled 4.39 million cruise passengers last year, up 82 percent on the previous year. The country is expected to become the second-biggest cruise market in the world, after the United States, by 2020. [Photo provided to China Daily]

Parent-child trips, such as the one featuring a chance to see dolphins in Yatsushiro, saw bookings surging 600 percent month-on-month in July.

Yuan Ping, the senior sales vice-president with Hong Kong-based Genting Cruise Line, says: "Our cruises for July and August sold out."

The cruise company has arranged special events for children, including science education lectures and fencing training, says Yuan.

"Cruises are good options for family travelers who have the elderly and children with them," she says, explaining that they don't have to move around checking into hotels or taking buses, and there is a lot of entertainment to ensure quality family time together.

Genting's ship currently covers Tokyo, Osaka, Fujiyama and Kagoshima.

Ctrip's cruises have also integrated a penguin attraction in Nagasaki, Universal Studios in Osaka and the aquarium in Fukuoka for cruise passengers with children.

Chinese food is also available.

Meanwhile, China is the fourth-biggest cruise market globally, says a report of the Beijing-based World Tourism Cities Federation's cruising branch.