The following are the documents you will need to ensure entry to the U.S. while on post-completion OPT:
- valid passport
- current unexpired F-1 visa stamp
- I-20 signed within the last 6 months
- EAD (OPT card)
- job offer letter or letter confirming current employment
The job offer letter or letter confirming your current employment should describe the job as temporary (no more than 12 months) because the idea behind Optional Practical Training is that it allow you to gain training in a temporary position in the U.S. An offer of permanent employment may be construed as inconsistent with holding non-immigrant status in the U.S.