Rules are Different for Researchers and Professors
Time spent in the United States as a J-1 Exchange Visitor or J-2 dependent affects when you are eligible to re-enter the US as a research scholar or professor. If you have previously been here as a research scholar or professor, it also affects when you can come back to the US. Periods when researchers or professors are not eligible to enter the country are called 12-month and 24-month bars.
If you enter the US under another J-1 category, including short-term scholar, specialist, or student intern, the bar does not apply to you.
It also does not affect people who are transferring to another institution to continue their current J-1 programs.
Have you been in the country for six months
The 12-month bar prohibits exchange visitors from starting a new program in the research scholar or professor categories if they were in the US for more than six months in any J status—including J-2 dependent—during all or part of the 12-month period immediately before the start date of their new program. If any part of a J-status exchange visitor’s presence in the US was within the 12-month period, the entire duration of his or her presence in the US while participating in an exchange visitor program is counted.
Were you a professor or research scholar before this?
If you have participated in the exchange visitor program as a professor or research scholar, you are subject to a 24-month bar. You must wait two years to repeat your participation in either of those categories.
The 24-month bar applies whether or not you actually complete your first five-year program. You cannot access unused time.