🌴 COUNTRY A California VS 🇲🇽 COUNTRY B Mexico

California's Franchise Tax Board (FTB) is among the most aggressive in the US at pursuing former residents who retain California ties. To successfully terminate California residency, you must: (1) establish domicile in a new state or country with clear intent to remain; (2) sever California ties — sell or rent out your California home, change your driver's license, voter registration, and vehicle registration; (3) if relying on the employment-related safe harbor, stay outside California for an uninterrupted 546 consecutive days (FTB Pub. 1031); and (4) ensure your primary social, economic, and family connections are outside California. High-income departures are frequently audited. Retaining a California tax attorney is strongly recommended for anyone earning over $200,000 before leaving the state.

Potentially yes — Under Article 9 of Mexico's Federal Tax Code, you are generally a Mexican tax resident if you establish your principal home (casa habitación) in Mexico; if you also keep a home abroad, you are resident when your center of vital interests is in Mexico. A day count alone does not decide residency. California remote workers who work in Mexico for shorter periods while maintaining their US domicile and primary home typically do not trigger Mexican ISR obligations on their foreign-source income. However, registering for a Mexican RFC (tax identification number), signing a long-term lease, or taking steps that suggest permanent establishment can trigger residency regardless of day count. The safest approach involves tracking days meticulously and avoiding actions that establish a home or main economic interests in Mexico.

At $100,000 income, a California resident pays approximately $5,069 in state income tax plus approximately $13,170 in US federal income tax — a combined burden of roughly $18,239. A Mexican tax resident earning the equivalent pays approximately $26,500 in ISR (at about MXN 18 per USD) — about $8,275 more than the combined California burden. This surprises many people who assume Mexico is a low-tax jurisdiction. The real financial advantage of Mexico is not income tax savings but rather the massive reduction in cost of living — housing, food, services, and transportation cost dramatically less. For Californians, the financial case for Mexico typically rests on total cost of living savings, not income tax reduction.

Yes — American citizens must file US federal income tax returns on their worldwide income regardless of where they reside. Moving to Mexico does not eliminate the US federal filing obligation. The US-Mexico tax treaty and the foreign tax credit mechanism prevent double taxation: Mexican ISR paid can be credited against the US tax liability on the same income. For Americans earning exclusively foreign-source income, the Foreign Earned Income Exclusion (FEIE) may eliminate the federal tax bill if they establish Mexican residency and meet the 330-day physical presence test. FBAR reporting (FinCEN 114) is required for Mexican bank accounts with aggregate value exceeding $10,000 at any point during the year.

The RFC (Registro Federal de Contribuyentes) is Mexico's tax identification number, issued by SAT (Mexico's tax authority). Americans who establish Mexican tax residency are required to register for an RFC and file annual ISR declarations. However, obtaining an RFC is not strictly required for Americans simply visiting or working remotely in Mexico for short periods without establishing residency. Caution: some landlords, banks, and government services in Mexico require an RFC even for foreigners. Applying for an RFC without fully understanding the residency implications can inadvertently trigger Mexican tax obligations. Consult a Mexican tax advisor before registering if you are uncertain about your residency status.

Yes — Americans who establish Mexican tax residency and meet the IRS Physical Presence test (330 days outside the US in a qualifying 12-month period) or Bona Fide Residence test can claim the Foreign Earned Income Exclusion (Form 2555). The 2026 FEIE limit is $132,900. For Americans earning from US employers while in Mexico but staying under the residency threshold, FEIE does not apply because they have not established foreign residency. The interaction between FEIE and the foreign tax credit for US-Mexico situations requires careful analysis: in some cases claiming FEIE worsens your overall position by forfeiting excess foreign tax credits from Mexican ISR payments.