There were plenty of furtive glances among the 100 or so Thais gathered at the temple southwest of Seoul. Though still only autumn, some wrapped themselves in thick winter clothing.
It was the end of Buddhist Lent and a Sunday, a time to gather at Buddharangsi Temple in Hwaseong, southwest of Seoul. A temporary bank booth was set up as usual to allow the workers to send money home to their families.
This time there were fewer than half the normal number. Stricter random checks by Korean authorities for undocumented workers have seen many illegal Thai workers sent home.
The few that remain regularly visit the Buddhist temple for religious purposes, sign the book of condolences, and transfer money to their families in Thailand at the temporary bank booth.
A 36-year-old woman from Sa Kaeo who arrived in South Korea last winter with her husband said she wasn't sure how many more winters she could survive in the terribly cold weather.
"My eldest son will enter conscription soon, and I've another in Prathom 3 [third grade] to feed," she said as she glanced suspiciously around. She is an illegal, not in South Korea under the state-recognised Employment Permit System (EPS).
She rarely travels far from the factory where she and her husband work. But last Sunday was a special occasion and she wanted to catch up with other Thais and do errands at the temple.
A native of Udon Thani, who declined to provide his name, goes to the temple for the first time to transfer 20,000 baht to his family in Ban Phue district, and said he arrived in South Korea six months ago without going through any broker or EPS channel.
"The [temporary booth] deducts just 1,500 won [about 45 baht] for each transfer, compared to the 5,000 baht I gave to a Thai guy who offered the same service in past months," said the 40-year-old northeastern native who previously worked in an industrial zone in Chon Buri province.
These people are just a small part of the vast number of undocumented migrants in South Korea, the world's 11th largest economy. According to Korean immigration statistics in March, Thai undocumented immigrants numbered 52,435, or 58.1% of the 90,235 Thais in the country.
According to the Thai embassy, if the trend persists, Thailand will have the highest number of undocumented immigrants in Korea.
One of the measures to halt this trend is denial of entry. The number of Thais denied entry to Korea last year topped 20,000. This year an even higher figure is expected. Last year also saw 8,402 Thais voluntarily deported, and the number will certainly increase this year, sources said. Deported undocumented immigrants are blacklisted by Korean authorities for five years.
Kanjana Wongsuwan, a labour counsellor at the Thai embassy, said Thai authorities have always encouraged workers to go through legal channels.
"If you're undocumented, there'll be more trouble as you may not have insurance -- for example, a night in ICU can cost a million won. You also get abused -- like masseuses being detained in bars," Ms Kanjana said.
She said many Thais are attracted by the higher earning potential in South Korea. "In Thailand, you get 300 baht a day, but here you may get 300 baht an hour. Korean banks also allow foreigners to open an account with only a passport. So even undocumented migrants can transfer money home with cheap fees."
Many Thais exploit loopholes in the 90-day free visa, and each year the number of deportations grows, Ms Kanjana said. Unusual and untimely deaths are also growing, from 40 in recent years to 71 cases now, many due to stress and heart failure.
The Thai embassy, she said, issues regular notices to warn Thais not to abuse the generosity of the Korean government which has granted a visa exemption to Thailand as one of 16 nations which helped in the Korean war.
It was particularly concerned about women going to work illegally as masseuses. There are no Thai-operated spas or massage salons in South Korea as the Medical Service Act preserves this work for visibly-impaired and trained practitioners only.
Setthawut Chansemawat, a Sukhothai native who has worked legally in Korea for more than eight years, said the labour law has improved. However, Thai workers are facing more thorough immigration surveillance and checks though factory audits, street CCTV checks and urine sampling because of the increased number of illegals.
"If not, there would be many more Thais turning up for temple events," he said.
Thai authorities in Thailand and Korea should continue their efforts to spread information. He said there is a need to prevent people from abusing each another or getting involved in illegal occupations which is having a negative effect on Thailand.
Veerayut, who did not want his last name published, said working in Korea has boosted his household income and allowed him to send his oldest child on to Mathayom 3 and ensure schooling for his nine-month old baby.
"My father used to work in Saudi Arabia and the remittance helped our situation," said Veerayut, 36, who has a Mathayom 6 education and a farming background from Nakhon Sawan's Takhli district.
Saowalak Krabuanphon, 38, a staff member of South Korea's Kim Hae Labour Support Unit, said the economic situation in Korea might not be as good as in the past and smaller businesses were closing down and laying off foreign workers.
"I'm helping with 10 lawsuits a month for Thais involving late or no compensation for being laid off and for closures, as well as zero or delayed top-up pensions by employers," said Ms Saowalak, who has lived in South Korea for 15 years and worked in the state agency for nine years.