It's that time of the year - the summer vacation brings glad tidings for the tykes, but for their parents, it's the season when cortisol constantly vies with mercury to reach higher levels.

Stress can arise when a parent realizes either it's too late to buy affordable air tickets to island destinations or there's no accommodation available at child-friendly hotels or resorts.

According to Ctrip, an online travel agency, the number of internet searches for child-friendly hotels has surged five times from last summer. This summer, bookings for hotel rooms that can take in parents and two children have risen 80 percent year-on-year.

The number of traveling couples with more than one child has tripled. Such nuclear families prefer to stay at quality hotels. Five- or four-star hotels account for nine out of 10 such reservations, Ctrip said.

During the summer break, domestic trips outnumber outbound travels. Shanghai, Beijing, Chengdu, Xi'an and Chongqing lead the list of popular domestic destinations.

Among them, reservations for hotel rooms in Chongqing have risen the most, up nearly 100 percent year-on-year. Other cities have seen more than a 60 percent rise.

But room rates have been generally falling, except in Sanya, the coastal city in Hainan province, where per-night rates exceeded 1,000 yuan ($147.30) this summer.

What they offer is extraordinary. The Haitang Bay Crown Plaza of IHG group, which opened in March, offers special family suites that have a children's room where the latter can pitch their own tent, use a slide as a connector to the two floors of the loft suite, reservations for which have topped the hotel's bookings this month.

Traveling couples with children have increased in number. They visit theme parks, zoos, local aquariums and water parks in Sanya (and even elsewhere), given this summer's high temperatures, according to the report by Lvmama, a subsidiary of Ctrip specializing in online bookings of hotel rooms, flights and holiday packages.

New ways of group bookings facilitate young nuclear families to meet and bond with similar families during the summer trips and, in the process, save on costs.

Lvmama has found that nearly half of the children-friendly travel products are booked by families with more than two children. Of them, about 20 percent were colleagues or relatives who formed groups and embarked on summer trips.

Safety and a comfortable experience is what parents care during trips overseas. Ctrip experts found personalized trips with a chauffeured car or SUV are popular among parents with young children. Nearly 70 percent of families were willing to try such trips in June, a month that saw bookings surge three times year-on-year.