Coaches Andy Yuen and Steve Jones chose four core players - Gracie Mann, Courtney Cox, Cathy Chan Tsz-ying and Lee Tsz-ting - to represent the sevens squad at Thursday's flag presentation ceremony.
Hong Kong will be one of five teams, alongside China, Japan, Kazakhstan and Thailand, in the girls' Rugby Sevens event, which makes its Games debut on August 17. The teams will play in a round-robin competition before the top four teams advance to the semi-finals.
Gracie, 16, who plays scrum-half, has trained with Sai Kung Stingrays for the past six years alongside Courtney, 17, who plays as a centre or scrum-half. She believes China and Japan will be tough opponents at the Games.
"We played in a youth 15s tournament in Thailand in March and beat the Thai team quite easily," Gracie says. "Before that, we faced Japan in the International Youth Tournament held in Hong Kong and, although we beat them, the scoreline was close. As for China, some of their players came to Hong Kong last summer and outplayed us in training matches.
"Kazakhstan are an unknown team, but we don't really have any idea about how any team will perform at the Games until the official line-ups are announced."
Courtney says Hong Kong's tough fitness training will help them in the competition.
"We've had three training sessions a week, on Mondays, Wednesdays and Fridays," she says.
"On Fridays, we usually work on building up our strength. We do running and other fitness training, including lots of press-ups."
Tsz-ting, 17, who is part of the under-18 squad together with Gracie and Courtney, believes the switch from 15s rugby to sevens demands greater fitness and stamina from players.
"Sevens matches are much more intense," Tsz-ting says. "I've found the training and the games themselves much harder. Up to now, I've felt the team have not yet peaked and that we can still improve."
Prop Cathy Chan Tsz-ying, 15, is a new member of the under-17 squad. She says she is facing strong competition in her position. "I was playing as a fly-half or a centre, but our coach felt prop was a better position for me," Cathy says.
"But I am not confident I'll make the final squad of 12, because there are seven props among the 18 candidates.
"Each sevens team has two props, so we'll need only three or four in the final squad. It's going to be a real challenge to make the final squad."
The 18 girls hoping to be chosen have just completed an intensive three-day training camp to boost their skills and strength.
Dannii Cheung, the team manager, says the team hope to win a medal. "We don't know if there will be a bronze medal match on the final day as we've seen only the first two days' schedule," Cheung says. "The method of selection for the semi-final matches has not been announced either."