You can submit your STEM OPT extension application to USCIS as early as 90 days prior to the end of your current OPT period. We recommend that you submit your STEM OPT Request via OISS Connect and upload your I-983 no later than one month prior to the end of your current Post-Completion OPT. Please remember that your complete application must be received by USCIS before your current OPT period expires.
If you timely file your STEM OPT extension application, you will be able to continue working while your application is pending, until a final decision is made by USCIS or for 180 days beyond the expiration of your Post-Completion OPT, whichever comes first. It can take 90 days or more for USCIS to process STEM OPT extension applications. Please note that you should not travel if your post-completion OPT period has ended and you have not yet received your STEM OPT EAD.
STEM OPT Sample Application Timeline