Foreign tourists dressed in Korean traditional costumes, "hanbok," tour central Seoul, Oct. 16. Yonhap

Some Thai nationals are campaigning against visiting Korea and opting for other neighboring countries after a growing number of travelers from the Southeastern Asian country have been denied entry to Korea.

According to Thai media outlets, some travelers were denied a visit permit during the online application process or denied entry after arrival and sent back despite holding valid documents as immigration policies and procedures have been tightened in recent months.

The Korea Immigration Service introduced the online travel permit system, K-ETA (Electronic Travel Authorization), in September 2021 through which foreign visitors register their travel information and receive authorization before departure via the internet and mobile applications.

Korea announced it would temporarily allow travelers from 22 countries, including Japan, the United States and the United Kingdom, to enter the country without K-ETA registration until the end of this year. But Thailand was not on the list and many people applying for entry via the K-ETA registration have been denied.

The Bangkok Post reported, Wednesday, that the hashtags "Ban travel to Korea" and "Korean immigration office" in Thai language trended on X, formerly known as Twitter, capturing over a million posts over the weekend.

Under the trending hashtags, Thai users shared their negative experiences with Korean immigration including accounts of being denied entry and sent back to Thailand. Many said they would opt for neighboring countries like Japan and Taiwan that offer visa-free entry to avoid losing money and wasting time.

The Nation, another Thai news media outlet, also reported last week on Thais' sudden dislike of Korea growing out of the strict immigration screenings.

"Several Thais visiting Korea got stuck in the immigration process and were eventually sent back, no matter how many documents they presented to guarantee their credibility," according to a Thai X user, who believes Korea's immigration office is "one of the toughest in the world."

Another Thai X user said that he was "questioned ceaselessly like I'm some kind of criminal," while many accused Korea's immigration officials of often being rude to Thai travelers.

The issue has even prompted the Thai government to take action. Thai Prime Minister Srettha Thavisin said, Tuesday, the Thai government will assign related authorities to look into the issue.

Thailand's Prime Minister Srettha Thavisin speaks to media inside the Siam Paragon shopping mall in Bangkok, Thailand, Oct. 4. Reuters-Yonhap

Behind the strict scrutiny of Thais recently is the long-running issue of undocumented Thai immigrants, according to Korea's Ministry of Foreign Affairs and Ministry of Justice.

Around 157,000 Thai nationals are residing here without permits, justice ministry data shows. Most of them are "phi noi" or "little ghosts" in Thai, jobseekers who enter Korea as tourists and remain beyond their authorized period of stay to work in the manufacturing and agricultural sectors.

"In reviewing K-ETA applications, we review the applicants' record of illegal stay (in other countries), the purpose of visit and the possibility of seeking illegal employment," the justice ministry said in a released statement, Friday.

"Even after the authorization is granted, they can be denied entry at the immigration checkpoint if they fail to present their purpose of visit properly, or they are highly likely to engage in activities other than their original purpose."

Thailand was among the top visiting countries to Korea in Asia after China, Japan, Taiwan and Hong Kong before the pandemic. The inbound tourism from Thailand seemed to be on a recovery track, as data from the Korea Tourism Organization (KTO) shows over 269,000 Thais, around half of 2019's 571,610, have visited Korea so far this year.

Korea launched the Visit Korea Year 2023-2024 campaign, seeking to take advantage of the growing international popularity of Korean culture and propel the momentum of tourism industry's post-pandemic recovery to attract 30 million foreign tourists a year by 2027.

However, the immigration issue is putting the country's goal at risk, as Thai travel agencies and tourists are now turning their back on Korea.

Go Jae-il, executive director of Bangkok-based Kokin Air Travel, told The Korea Times, Friday, that a "growing number of Thai travel agencies are losing interests in selling travel packages to Korea" due to immigration issues.

He confirmed the complaints among Thai travelers started to grow from the beginning of this year, as many were denied travel despite holding valid documents and proving stable economic income and profession.

"Even though the KTO would like to increase the Thai market this year to the 2019 level, it may prove difficult because of growing concerns among Thai travelers," Charoen Wangananont, president of the Thai Travel Association, was quoted as saying by The Bangkok Post.

In response, the Korean government is seeking ways to resolve the issue.

Jointly with the justice ministry, the foreign ministry is working to "seek ways to redeem the immigration system while maintaining screening (for possible illegal immigration)," a ministry official said.

Korean First Vice Foreign Minister Chang Ho-jin and Thailand's Permanent Secretary for Foreign Affairs Sarun Charoensuwan shake hands during the fourth round of bilateral policy consultations in Bangkok, Nov. 3, in this photo provided by Seoul's foreign ministry. Yonhap

Korea and Thailand will soon hold talks between the directors-general for consular affairs at their respective foreign ministries to discuss the matter, the foreign ministry said, Saturday.

The decision was reached during First Vice Foreign Minister Chang Ho-jin's official travel to Thailand where he met Thailand's Permanent Secretary for Foreign Affairs Sarun Charoensuwan in Bangkok for the fourth round of bilateral policy consultations, Friday.