Filing Status Question: US Citizen + Irish Spouse (Green Card Received Dec 2025) — MFJ vs MFS, and Treaty Considerations

[TaxMan2026]

My wife and I married in February 2025. She is an Irish citizen. Here is our specific timeline:

• February 2025 — We married
• Late March 2025 — She moved to the US on a J-1 visa and began working for a US employer on a W-2 basis 
• Received FICA tax refund in November 2025 as a nonresident employee.
• Late December 2025 — She received her marriage-based Green Card, making her a lawful permanent resident

Prior to moving to the US at the end of March, she was living and working outside of the US.

My understanding of her tax residency status:

Because she was physically present in the US from late March through December 2025, I believe she meets the Substantial Presence Test (well over 183 days), making her a US tax resident for the full year 2025 — even before the Green Card arrived. However, I'm not certain whether the IRS would instead treat her as a dual-status alien (nonresident → resident), given that she only moved in late March.

My questions:

1. Is she considered a full-year US resident for 2025 via the Substantial Presence Test, or is she treated as a dual-status alien with a residency start date of late March?
2. If she is dual-status, does that prevent us from filing jointly (Married Filing Jointly), and would we be forced to file separately?
3. Would the FICA tax refund for her time on a J-1 visa before the green card contribute to our joint taxes or need to be adjusted for in some way?
4. If she can elect to be treated as a full-year resident (I've read about a joint election for this), is that typically the more cost-beneficial option for a dual-income couple?
5. For the period before she moved to the US (January–late March 2025), she had Irish-sourced income. Does the US-Ireland tax treaty provide any exemption or reduced taxation on that pre-move income? Or does the treaty's saving clause effectively eliminate any benefit once she's classified as a US resident?
6. Should we expect to file Form 1116 (Foreign Tax Credit) for any Irish taxes she paid on pre-move income?

Any guidance is greatly appreciated!

[AmyC]

1. A single person would default to dual status. 

2. As a married person, you can file MFJ for the entire year.

3. FICA refund is not part of your tax return. No need to repay it.

4. MFJ is the most beneficial route generally.

5. MFJ does require all world wide income be included but you may have income that is exempt or reduced due to the treaty. See Ireland treaty.

6. Yes, any remaining foreign income that was taxed can use Form 1116 to claim a foreign tax credit against your US tax. See Where do I enter the foreign tax credit (Form 1116) or deduction? Rare is the person claiming the deduction. The credit is for more common but you can try it both ways, if you itemize.

You can't exempt income and claim a credit for the tax paid. It is either / or. 

Congratulations on your first anniversary!

[TaxMan2026]

Great, thanks very much!