Yes, you will need to file an extension and pass the substantial presence test before filing. It appears you can make the first-year election but the first day of residency is still 1 Oct and you and your spouse would non-resident before that. So dual status still applies.
Then having dual status in the same tax year and if you meet the remaining criteria on page 8 of Publication 519, you can then make the election to be treated a residents for the entire year.
You will need to print and mail your returns and attach statements for both elections per the instructions on pages 8-9 of Publication 519
First-year election:
1. Be present in the United States for at least 31 days in a row in 2021, and
2. Be present in the United States for at least 75% of the number of days beginning with the first day of the 31-day period and ending with the last day of 2021. For purposes of this 75% requirement, you can treat up to 5 days of absence from the United States as days of presence in the United States.
Election to be treated as residents for the entire year:
You were a nonresident alien at the beginning of the year.
• You are a resident alien or U.S. citizen at the end of the year.
• You are married to a U.S. citizen or resident alien at the end of the year.
• Your spouse joins you in making the choice.
This includes situations in which both you and your spouse were nonresident aliens at the beginning of the tax year and both of you are resident aliens at the end of the tax year.
**Say "Thanks" by clicking the thumb icon in a post
**Mark the post that answers your question by clicking on "Mark as Best Answer"
