Around 200 form five pupils left Hong Kong for Guangzhou and Shenzhen on Monday, becoming the first group to take part in a compulsory trip to the mainland as part of the Citizenship and Social Development subject.

Chief Secretary Eric Chan said tours like this are key to the students' future prospects.

A boy surnamed Niu told RTHK he was excited about the overnight trip.

"We'll study at a mainland secondary school alongside the students there. Then, we'll go to some tourist attractions and historic sites. I hope to meet more new friends there," he said.

"After this study tour, we have to write a report on how the Greater Bay Area can help Hong Kong teens."

Chan was at West Kowloon Station to see them off.

"They will be in form six next year, and taking their DSE exams. It's an important moment as they have to choose their subjects for university," he said.

"When the students go to the mainland, they can see the country's development. This will help them to find out what they are interested in. It will then be easier for them to choose subjects in future."

Chan said the government aims to arrange mainland study tours for 40,000 senior secondary school students this academic year.