Two men, Dang Xuan Tuan, 42, and Pham Trung Tan, 39, and one woman, Tran Thi Huong, 44, are believed to have assisted four Chinese citizens enter Vietnam illegally to find jobs.
Residents of Phuc Yen Town spotted the four Chinese waiting for a ride on May 6 and called the police. When the police arrived, they tried to flee but failed.
At the police station, they produced no ID. They said they were waiting for someone to take them to a workplace after having taken a taxi from Lao Cai Province, which borders China.
Police found that Tuan, Tan and Huong had brought the Chinese into the country. The case is being investigated further.
On Friday, two men in Ho Chi Minh City were arrested for smuggling illegal entrants from China.
Vietnam has ramped up border control measures recently after detecting a rising influx of illegal entrants from surrounding countries amid the pandemic.
The nation's fourth Covid-19 outbreak has seen 256 community transmissions in 24 localities since late April.