1. Regardless of the published application deadlines of programs to which you will apply, your applications(s) should be in by no later than the end of the third week of the semester prior to the semester that you plan to be abroad. This is because....
A) Some programs, even though they do not publicly say so, do rolling admissions. And of course, some do so publicly. If your chosen program is full by the time your application reaches it, even though your application gets there in advance of the program's published deadline, no matter how strong an applicant you are, at best you will be wait listed, in which case your prospects of eventual admission will be poor. More likely, you will simply be turned down.
B) Many countries which host programs attended by Swarthmore students require entry visas of visiting students. And may of these same countries have recently made the visa application process more time consuming and complicated. This is just about certainly in retaliation for the post 9/11 difficulties the US has created for foreign students who wish to study in this country. Nothing can be done about this. If you plan to study in a country that requires visas of visiting students, it's a simple either/or: Either you follow their instructions to the letter, or you won't study there. For many, perhaps the majority, of programs to which our students apply, the earlier you apply the earlier you will receive your acceptance. It is now more important than it has been until recently to have added time for the visa application Applying to your program(s) early is usually a good way to ge this extra time.
2. For a small minority of programs attended by our students, even getting the application in by week two or three of the semester prior to study abroad is not soon enough. A small number which do rolling admissions fill up before this, sometimes week or even months before. Some programs - e.g., Oxford and Cambridge for Spring semester junior year- have unbelievably early application times. For these two universities, you would want to apply - for Spring junior year - by winter break sophomore year. It is your responsibility to know whether or not a program in which you are interested is one of these programs. Of course, you may be in touch with the program directly. Just about always, asking at the Foreign Study Office about a program of interest to you will provide you with this information.
If you think that you may wish to study abroad, having your first discussion with the study abroad adviser during the second half of the first semester of your first year is not jumping the gun. Even earlier if you are so disposed. However focused or unfocused your thinking is about study abroad, you will be welcome for an exploratory discussion in the Foreign Study Office. And , as much experience teaches, just about always such a discussion will be useful to you.