After finishing my final year of medical school, I had a month off and considered taking the Step 3 in order to “get it over with” before PGY1 year. But after some thought and consulting individuals who had already moved to the U.S., I decided against it. While I do not advocate any specific time frame for taking the Step 3, I do encourage applicants to base their decision on the following considerations: specialty, visa status, specific program, and level of work experience in the U.S. before residency.
First all, if you are going into IM/FM or doing a preliminary medicine year, you will find that you learn quite a lot during the first year, and since the Step 3 has a higher percentage of medicine questions, it will likely be much easier once you have some months (even years) of general medicine behind you.
If you are going into another specialty that will remove you from general adult medicine, such as pediatrics, surgery, or psychiatry, it might benefit you to take the exam early in your PGY1 year, i.e. closer to the end of medical school. If you are already an experienced physician in your home country and entering medicine in the U.S., you might also feel comfortable taking it before starting PGY1 year in order to qualify for an H1 visa, another consideration that I will discuss shortly.
Also you will find that while most basic management is similar from country to country, there will be some differences, and studying alone might not suffice. In other words, a year of medicine in the U.S. might really benefit you in terms of succeeding on a test meant to evaluate clinical management in the American system.
Second, there is the visa issue. Step 3 is useful if you want to apply for an H1 visa as opposed to a J1, as Step 3 is not required for a J1. However, the H1 visa entails more paperwork and hassle for programs and, as a result, the majority of programs do not sponsor it (although some programs will consider it on a case-by-case basis). However, if the H1 is what you are going for, do not lose hope as there are a small number of programs that actually give preference to applicants who have already passed Step 3 and are going for an H1. Ultimately, you will need to judge for yourself, based on the programs you are considering or to which you have been accepted, whether the Step 3 will need to be done before starting.
Third, just as another consideration, some states do not allow international medical graduates to take the Step 3 before the end of their PGY3. In some ways it does not matter, because you can apply for it in any state, regardless of the state in which you are training, but you will still not be able to be licensed officially in those states until PGY3 year.
Lastly, some programs will actually pay for your Step 3, so be sure to check this before taking it once you have graduated!
In conclusion, there is no one way to plan the timing of the Step 3, it really depends on your specialty, visa requirements, and program, and it is beneficial to consider all of these aspects before deciding to sit the exam the moment you receive your diploma and ECFMG certificate. In my case, I decided to take it after my medicine prelim year but not too far into my neurology training, so as to avoid being too removed from IM. Best of luck regardless of your decision!