While you can study abroad as early as the summer after your freshman year, most international relations majors study abroad at the end of their sophomore or beginning of their junior year. Others situate their study abroad experience closer to their senior year so they can conduct research for their senior papers while abroad. Study abroad programs are also offered in the summer and during winter break. Whatever your year or situation, there are plenty of opportunities for you to coordinate study abroad with your major requirements .
Your freshman year is best spent fulfilling general education requirements  and deciding on your major (most international relations students declare their major at the end of their first year).
The summer after your freshman year is a great time to study abroad, though, especially if you want to get a head-start on fulfilling your foreign language requirements ; you might travel to a country that speaks a language you’re interested in learning, then return there once you’ve acquired more language skills.
The second semester of your sophomore year is a good time to study abroad, as well either semester during your junior year (it’s recommended that you participate in a semester-long program regardless of when you study abroad).
The summer after your junior year is also an option and a particularly good time to study abroad if you’re interested in using the experience to conduct research for your senior paper.
Senior year is an okay time to study abroad, just keep in mind that you need to take your senior seminar and complete your final paper at the University of Iowa. You’ll also need to double check that all of your requirements for graduation will be met upon your return.
If you can’t seem to fit study abroad in during the school year, consider a summer or winter program, e.g. the India Winterim  or the summer program at the Higher School of Economics in Moscow .