If he is caught and sent back to Vietnam, he fears he will not be able to pay back the money he borrowed to pay VND200 million ($8,540) as brokerage to a labor export company more than two years for getting a job in Taiwan.
At the time all he wanted was to be able to work as many overtime shifts as possible so that he can pay off the debts. But because of the Covid-19 outbreak and the fact that his employer did not let him work overtime, he lost out on some potential earnings.
Meanwhile, out of his monthly basic salary of TWD25,000 ($808.70), he had to pay TWD16,000 for food, lodging, brokerage, and insurance premiums, leaving him with only TWD9,000–10,000 to spend, save or send home.
He says the pay was "even less than the salary Vietnamese workers get if they work overtime back home," and that he had not received any bonuses or any other financial support to fall back on if things went wrong.
He was so unhappy and concerned about his future that he quit his contracted job and became an illegal worker, reasoning that he would only have to pay for food and rent and not insurance premiums and commissions.
He is constantly worried about being detained or deported by immigration authorities. The fear has been exacerbated by the fact the government has stepped up efforts to crack down on illegal immigrants.
Tuan is one of many Vietnamese to work without legal documents in foreign countries because they can earn more money in informal jobs than in permitted and legitimate companies.
In fact, this issue has been in the limelight for quite some time now.
Over 25,000 Vietnamese living overseas have been deported for breaking local laws since 2018, according to a public security ministry statement in June.
"Vietnamese abroad have become the main subjects of investigation for authorities [in other countries] during campaigns to search for illegal workers," Deputy Minister of Public Security Luong Tam Quang says.
On August 19 the South Korean Ministry of Justice reported that in the previous two months it had apprehended 642 undocumented foreign workers, 49 of them Vietnamese.
In Japan too, many Vietnamese workers are said to be hiding in the countryside. There were 7,167 reported cases of people absconding to work illegally last year, more than 60% being trainees from Vietnam, Nikkei Asia said in an article in July.
Though no exact statistics are available, thousands of Vietnamese are thought to be working illegally in places like Taiwan, Japan, South Korea, Thailand, the U.S., and Europe.
The number of legal guest workers is around 600,000.
According to the Department of Labor, War Invalids, and Social Affairs in Thanh Hoa Province, which has more than 32,000 people working abroad, many workers overstay their visa and instead seek jobs unlawfully abroad.
In fact, 890 out of more than 6,000 workers from the province (8.77%) working and living in South Korea are undocumented, it says.
Though the payoff is substantial, so is the risk of being caught by authorities, meaning undocumented people must live underground and keep a low profile to avoid being arrested and deported.
Phuc Doan, like Tuan, has been living in constant fear of being detected by immigration officials since becoming an illegal worker over a year ago.
After he finished work at around 5 a.m. he goes grocery shopping at a local supermarket before going straight home at around 6 a.m.
He says if accosted by a cop on the street he will pretend as if he had drunk in a karaoke bar or a restaurant, and if questioned aggressively or asked to provide his residency permit, he will simply flee.
"Because I can't go out, I have to eat at home," he explains, adding that he always buys enough food to last a week and keeps cooked food in the fridge.
The government's broadening of the search for undocumented workers and immigration raids also make it more difficult for undocumented people to find jobs and housing.
Lam Trong, who overstayed his tourist visa in South Korea four years ago, says authorities send police officers to raid construction sites "at any time" and "anywhere" to look for illegal immigrants, making it difficult for him to find work.
He recalls a time when the police stormed a building where he was working and searched the place with a fine-tooth comb in an attempt to catch illegal workers in the act.
"People yelled 'Cops!' and fled in all directions."
People working on the upper floors rushed downstairs to escape and illegal workers were pushing and shoving to get out.
"Because construction sites are a dangerous environment, many people have been injured or killed while attempting to flee."
In the worst case, he will have to quit the job and look for another one though he will probably lose the pay for the days he worked.
He also says undocumented workers like him prefer to live in semi-basement flats so that they can escape quickly and easily if necessary. Those who live upstairs often find a room with a window.
If they end up fleeing, they lose the security deposits made with their landlords.
Everyone who works in the country illegally is expected to follow two practices: conceal their faces at all times and stay away from hospitals.
Trong wears a mask and a hat to fully cover his face.
"I rarely interact with others and I always check my surroundings and stay cautious at all times."
Undocumented workers are hesitant to go to a hospital even if critically ill for fear of being asked for their identity. So they mostly go to pharmacies to stock up on medicines and herbal remedies to treat themselves at home.
But despite having to live in cramped places and constantly facing risks, many Vietnamese accept their lot to send more money home because they can get paid more as non-contracted workers.
According to the Ministry of Labour, Invalids and Social Affairs, Vietnamese contracted workers can make $1,200-1,400 a month in Japan and $1,400-1,800 in South Korea, two of Vietnam's major labor export markets.
Many employers in South Korea prefer hiring undocumented workers because it means they do not have to sign contracts or provide insurance while the employees can get higher wages.
Bao Long, like Tuan, hoped to leave for another country in search of a better livelihood. In 2019 he paid a broker VND150 million to get a job at a Japanese company that specialized in air-conditioner installation, and he worked eight hours a day and made around VND30 million a month without having to work overtime.
During his second month at the job, the company increased the working hours but not the pay.
"We were threatened on a daily basis if we did not comply with the rules," the 25-year-old native of Nghe An Province says.
Within two weeks he and two Vietnamese coworkers left the company to look for another job, and applied at a food processing company. Long was hired as a shipper with a monthly salary of around VND80 million.
He has been an illegal immigrant for nearly three years, working four different jobs. He has paid off all of his debts and saved over VND600 million.
Le Thanh Tung, deputy head of the Thanh Hoa Province labor department, said at a conference on labor export held in the province in mid-August that the relatively high wages in South Korea are why migrant workers choose to overstay or break the contract they sign.
In some cases the salaries are 7-10 times what they might get in Vietnam, besides which they cannot find jobs with similar salaries if they return home, he said.
Since many aspiring guest workers are from rural areas and do not have a lot of savings, they usually have to borrow money to pay the big brokerage labor export firms charge, which puts pressure on them to earn as much money as quickly as possible to pay off that debt.
A survey by Japan’s Immigration Services Agency between December 2021 and April this year of around 2,100 technical trainees found that many Vietnamese had to pay large brokerages to get to Japan.
Vietnamese labor agencies get paid an average of ¥688,000 ($4,893) compared with ¥94,000 in the Philippines, it found. It also said 55% had to borrow money to pay the brokers, with 80% of them borrowing ¥674,000 on average.
Ingrid Christensen, director of the International Labor Organization Vietnam, said at a conference last month that Vietnamese workers have to pay an average of VND165 million to land their first overseas job, or equivalent to eight months' salary. This forces many Vietnamese to become undocumented workers to avoid running up more debts, she pointed out.
With this issue becoming a growing worry, the Vietnamese government is stepping up efforts to prevent workers overstaying or working illegally in foreign countries.
The Ministry of Labor, Invalids, and Social Affairs suspended recruitment of guest workers for South Korea under the Employment Permit System in eight districts in the four provinces of Ha Tinh, Nghe An, Hai Duong, and Thanh Hoa in July.
This was after more than 27% of workers from those places failed to return in time or violated their contracts.
But this battle seems to have no end in sight, with officials struggling to persuade illegal workers to return home.
"There are provisions to penalize such acts, but since [the offenders] are abroad, authorities here cannot do anything," Tung said.
Many nations have ramped up efforts to deport foreign nationals staying illegally.
Trong claims he is willing to give up his youth, health and personal happiness to earn a higher salary abroad.
"There are a lot of manual jobs here, and the pay is better than I can get back home [in Vietnam]."
"So though I have to give things up, I am willing to do it for my family."