Dive Brief: 

• New international student enrollment dropped for the third-straight year in the 2018-19 academic year, according to annual data released by the Institute of International Education. 
• Fewer foreign students headed to the U.S. for undergraduate and nondegree education, with those groups declining year-over-year by 1.5% and 5.7%, respectively. However, a 1.6% gain in international graduate students partially offset those losses. 
• Despite those trends, the number of international students in the U.S. reached a record high of 1.1 million in 2018-19, a year-over-year increase of 0.5%.

Dive Insight: 

Although the number of international students in the U.S. hit an all-time high, growth has slowed for the fourth-straight year. Moreover, those gains were largely driven by increased participation in the optional practical training (OPT)​ program, which lets foreign students work here in their fields of study for one to three years after graduation. 

OPT participation grew by 9.6% in 2018-19, reaching a record high of nearly 223,100 students. Meanwhile, the number of total enrolled international students, a figure that doesn't include OPT, fell 2.1% to about 872,200 that year. 

The OPT program has continued to grow after it was expanded in 2016 to let STEM students stay in the U.S. for up to three years after graduating. However, colleges have complained this year that students who have applied for the work authorization program are experiencing months-long issuance delays.

That could hamper current program participation and lead to slower growth or even declines next year, said Rahul Choudaha, an international education analyst, in an interview with Education Dive. 

International students hoping to study in the U.S. are facing similar problems. Dozens of colleges — including elite institutions such Harvard, Yale and Princeton universities — have urged the U.S. Department of Homeland Security (DHS) to expedite visa approvals so they don't lose out on their international students. 

"Increasingly, visa delays are making these scholars' attendance and engagement in the university unpredictable and anxiety-ridden," Harvard President Lawrence Bacow wrote to the department earlier this year. 

An ongoing trade war with China may also cause international enrollment declines. Growth in Chinese international students has continued to slow in 2018-19. Earlier this year, a Chinese education official warned the country's students about the "risks" of studying in the U.S. 

Those trends are hurting some colleges that rely on tuition revenue from international students, who often pay more than their domestic peers. While highly ranked colleges may be shielded from the trend, Choudaha said, less selective institutions and some public universities are already seeing big losses.

Public universities in Iowa, for instance, have seen a 44% decrease in Chinese students since 2015, and Arizona State University has seen a 20% drop in Chinese students since 2016, according to local media reports. Earlier this year, nine Chinese students who were returning to Arizona State were denied entry at an airport. 

Colleges are waking up to these trends, Choudaha said. "They need to, first of all, temper down their growth expectations for China, but at the same time start investing (in) new source countries," he said. "The mindset has started shifting that they need to do more."