They were charged with allegedly organizing and directing criminal gangs, illegally opening casinos, wildlife trafficking, deliberately causing injuries, and illegally detaining people that led to their death.
The Ministry of Public Security of China asked for support from Vietnam in searching for the duos.
Khanh Hoa, which welcomed over 700,000 Chinese visitors so far this year, has in recent years discovered foreign tourists who are fugitive criminals.
In November 2017, the provincial police seized two wanted Chinese criminals from Guangzhou province. In June 2017, two other Chinese criminals from Guangdong province gave themselves up to Khanh Hoa police.