This question came up in the Ensenada Expats Facebook group last week. Chuck MacKinnon was selling his US home and moving to Mexico full-time and wanted to know whether he’d owe Mexican taxes on the sale.
The comments were a mix of reasonable instincts, confident misinformation, and one guy citing Gemini. I jumped in with the short version. I said I’d write the longer one.
Here it is.
The short answer: Most American retirees living in Baja can legally maintain US tax residency, owe Mexico nothing on their Social Security, pensions, and investment income, and keep their entire financial life in the United States — where it already is. The key is understanding that your immigration status and your tax status are two completely separate things.
The Bottom Line (Read This Even If You Skip Everything Else)
- Living in Mexico full-time does not automatically make you a Mexican tax resident.
- Mexico’s residency test is based on where your economic life is rooted, not how many days you spend here.
- If your income is 100% from US sources — Social Security, pensions, 401(k), investments — Mexico has very little legal basis to tax you.
- If you did become a Mexican tax resident on $50,000/year in US income, you’d owe around $11,000 to Mexico on top of whatever you already pay the IRS.
- Three things protect you: keep a real US home, stay off SAT’s radar (no RFC, no Mexican bank account), and sell any US property before you establish roots here.
- This isn’t a loophole. It’s how the law actually works.
Why does any of this matter? The $11,000 math.
Mexico taxes its tax residents on worldwide income — every dollar you earn anywhere, at Mexican rates. The rates are progressive and top out at 35%, with the 30% bracket starting around $38,000 USD equivalent in 2026.
Run the numbers for typical Baja retiree income:
| Annual US income | Mexican ISR owed | Effective rate |
|---|---|---|
| $30,000 | ~$5,450 | 18.2% |
| $50,000 | ~$11,200 | 22.4% |
| $80,000 | ~$20,500 | 25.6% |
These are raw numbers before any credit. And — critically — you'd still owe US taxes too. Mexico and the US have a tax treaty that prevents true double taxation, but it does not make Mexican taxes disappear. The Foreign Tax Credit helps, but it doesn't fully bridge the gap when Mexican rates exceed US rates on the same income. More on that below.
Cross-border CPA fees to manage dual returns properly run $1,500–$5,000 per year. That's on top of the tax itself.
For a retired couple living comfortably on $60,000 in US income, the total cost of accidentally becoming a Mexican tax resident can easily exceed $13,000 annually. That's not a theoretical risk. That's a vacation fund, a medical bill, or a year of groceries.
The 183-Day Myth
The most common wrong answer in that Facebook thread — and in most expat Facebook groups — is some version of: “If you stay more than 183 days, you’re a Mexican tax resident.”
This is not how Mexican law works.
Mexico does not have a day-count test for individual tax residency. What it has is a home test. Under Mexico’s Federal Tax Code, you become a tax resident if you’ve established your permanent home here. If you also have a home in the US, Mexico then looks at where your economic life is actually centered — specifically, where your income comes from.
If your income is 100% from the United States, Mexico cannot win that test.
The actual law: CFF Article 9 and the vital interests test
Mexico's Federal Tax Code (Código Fiscal de la Federación, or CFF) governs tax residency under Article 9, Section I. An individual is a Mexican tax resident if they've established their casa habitación (permanent home) in Mexico.
If they also have a home outside Mexico — as most US expats do — the tiebreaker is the centro de intereses vitales (center of vital interests). Mexico wins that tiebreaker only if either:
- More than 50% of your total annual income is sourced from Mexico, or
- Mexico is the primary location of your professional activities.
A US retiree whose income is entirely Social Security, pension, 401(k)/IRA distributions, dividends, and interest from US institutions fails both tests structurally. Zero percent of income is Mexican-sourced. There are no professional activities in Mexico.
Three other things that get the law wrong in common expat conversation:
- Immigration residency ≠ tax residency. Holding a Residente Temporal or Residente Permanente card does not trigger CFF Article 9. The INM (immigration) and SAT (tax) run completely parallel systems.
- There is no 183-day rule for individuals. The day-count appears in employment contexts and treaty provisions for short-term business assignees. It does not apply to retirees.
- Short-term vacation rental use is explicitly carved out. CFF Regulations Article 5 states that persons temporarily occupying property for tourism purposes have not established a habitual abode.
The risk vector is narrow but real: if you have no US home at all — you sold it and moved here completely — then Mexico has a strong argument that your permanent home is in Mexico, and the vital-interests analysis becomes more relevant. The defense is maintaining a genuine US permanent home with documentation: a lease or property tax bill in your name, utility bills, mail, and periodic physical use.
Your Immigration Card and Your Tax Status Are Different Things
This is the piece that confuses people the most. You can hold a Residente Permanente card, live here 365 days a year, drive on Mexican roads, shop at Calimax, and still be a US tax resident for legal purposes. The INM (immigration agency) and SAT (tax authority) do not talk to each other. Getting a residency card does not register you with SAT, does not create a tax file, and does not obligate you to file a Mexican return.
What does create a SAT file is getting an RFC number — Mexico’s tax ID. Once you have one, you have filing obligations. Don’t get one unless a specific transaction forces it.
This distinction matters enough to repeat: immigration permanent residency is not tax residency. They sound the same. They aren’t.
What You Actually Owe the US (And It’s Not as Bad as You Think)
Americans owe US taxes on worldwide income regardless of where they live. That’s citizenship-based taxation and it doesn’t change when you move to Ensenada. But for most retirees, the US bill is lower than people expect.
A married couple with $60,000 in Social Security, pension, and IRA income, filing jointly, taking the standard deduction plus the age-65 add-on, typically pays under $4,000 in US federal tax. That’s before any credits.
Social Security is taxed at 0–85% inclusion depending on your combined income — not a flat 85%. And a significant portion of that is sheltered by the standard deduction anyway.
The Foreign Earned Income Exclusion (FEIE, Form 2555) that expats often talk about? It doesn’t apply to retirees. It only covers active wages and self-employment income you physically earn in a foreign country.
Why FEIE doesn't help retirees (and the FTC only partially does)
The Foreign Earned Income Exclusion (FEIE, Form 2555) excludes up to $132,900 in 2026 from US income tax — but only for income earned through personal services you physically perform in a foreign country. Under IRC §911(b)(1)(B), it categorically does not cover:
- Social Security benefits
- Pensions and annuities
- 401(k) and IRA distributions
- Dividends, interest, capital gains
- Rental income from US properties
That's essentially the entire income stream of a typical Baja retiree. FEIE is designed for expats with active foreign employment. It's not a retirement tax tool.
The Foreign Tax Credit (FTC, Form 1116) is more relevant but has a structural limitation. It offsets US tax only on foreign-source income. Your Social Security, US pension, US brokerage dividends, and IRA distributions are US-sourced under IRC §§861 and 865. A default Form 1116 produces zero credit limitation for these streams.
It's possible to invoke the treaty's re-sourcing rule (US–Mexico Treaty Article 24(3)) to recharacterize that income as foreign-source, claim a credit, and attach Form 8833 to disclose the treaty position. But even if that works perfectly, it only offsets your US tax on those streams — not the Mexican tax. If Mexico charges $11,000 and the US charges $4,000 on the same income, the FTC wipes out the US $4,000 and you still owe Mexico $7,000 with $4,000 of excess credit that carries forward but may never be usable.
The math consistently favors non-residency over attempting to manage dual-country tax liability on US-source retirement income.
The Treaty Protections That Actually Matter
The US and Mexico have had a tax treaty since 1994. For retirees, three provisions are genuinely powerful.
Social Security is untouchable by Mexico. Full stop. Even if you somehow became a Mexican tax resident, Mexico cannot tax your US Social Security under Article 19 of the treaty. It’s explicitly carved out from the rules that would otherwise give Mexico a claim.
Capital gains on US investments stay in the US. If you sell stocks, bonds, or other US assets, the treaty gives the US primary taxing rights. Mexico can’t grab a piece.
The tiebreaker rule backs you up. If both countries ever claimed you simultaneously, the treaty has a ranked test to determine which country wins. A US citizen with a US home, US bank accounts, US Medicare, and US family ties wins that test at step one or two — before it even gets to the day-count question.
Treaty article citations and the saving clause caveat
The governing document is the US–Mexico Income Tax Convention, signed September 18, 1992, in force December 28, 1993, amended by the 2002 Protocol. The US has not signed the OECD Multilateral Instrument (MLI), so only the original treaty and its two protocols apply.
Article 19(1)(b) — Social Security: "Social security benefits and other public pensions paid by a Contracting State to a resident of the other Contracting State or a citizen of the United States shall be taxable only in the first-mentioned State." This provision is explicitly carved out of the saving clause in Article 1(5), meaning Mexico cannot tax your US Social Security even if you're a Mexican tax resident.
Article 13 — Capital gains: Paragraph (1) gives the US primary rights on gains from US real estate. Paragraph (7) says gains on other property (US stocks, brokerage holdings) are taxable only in the alienator's residence state — which, if you maintain US treaty residency, is the US.
Article 4 — Tiebreaker residency: When both countries claim you as a resident under domestic law, the treaty resolves it hierarchically: (1) permanent home available, (2) center of vital interests (closer personal and economic relations), (3) habitual abode, (4) nationality, (5) competent authority mutual agreement. A US citizen who keeps a US home, US banking, US medical care, US driver's license, and US family ties almost always wins at step 1 or 2.
The saving clause (Article 1(4), post-Protocol): The US reserves the right to tax its citizens as if the treaty didn't exist, with narrow exceptions. Social Security under Article 19(1)(b) is explicitly excepted. Private pensions and IRA/401(k) distributions under Article 19(1)(a) are subject to the saving clause — meaning both countries can tax those streams, with the Foreign Tax Credit cleaning up the overlap (imperfectly, as described above).
Article 17 — Limitation on Benefits: Individuals automatically qualify under Article 17(1)(a). LOB is a corporate concern, not a retiree concern.
To claim treaty benefits on a US return that conflict with default IRS rules, attach Form 8833 (treaty-based return position disclosure). Failure to file Form 8833 when required carries a $1,000 per-item penalty under IRC §6712.
The Home Sale Trap (Read This Before You List)
This is where people lose real money. The Facebook question that started this post is actually the highest-stakes scenario in the whole discussion.
Under US law, you can exclude up to $250,000 in capital gains ($500,000 married) on the sale of a home you’ve owned and lived in for at least two of the last five years. That exclusion applies to US citizens no matter where they live when they sell.
Mexico does not recognize that exclusion.
If you sell your US home before you establish a permanent home in Mexico, Mexico has no claim. You’re not a Mexican tax resident yet. The gain is invisible to SAT.
If you sell after establishing permanent roots here, Mexico can argue it’s entitled to tax the entire gain — minus whatever you paid the US. On an $800,000 gain, that difference can exceed $150,000.
Sell first. Move second.
The actual numbers and how Mexican tax on home sales works
The US side: IRC §121 excludes up to $250,000 (single) / $500,000 (married filing jointly) on gains from the sale of a principal residence, requiring 2-of-5 years ownership and use. It applies to US citizens regardless of where they live at sale. This provision has nothing to do with Mexico.
The Mexico side: Mexico's primary-residence exemption under LISR Article 93 applies only to Mexican-situated homes. It does not apply to US properties. A Mexican tax resident who sells a US home owes Mexican ISR on the full gain, with a credit only for US taxes actually paid.
Scenario — MFJ couple, $400,000 basis, $1.2M sale price ($800,000 gain):
Sell before establishing Mexican tax residency:
§121 excludes $500,000. Taxable gain: $300,000. US federal LTCG + NIIT: ~$71,400. California (if applicable): ~$30,000. Mexico: $0. Total: ~$101,000.
Sell after establishing Mexican tax residency:
US tax unchanged: ~$71,400 (§121 still applies to US citizens). Mexico claims the full $800,000 gain at progressive rates up to 35%. Mexican ISR before credit: ~$230,000–$280,000. FTC for US tax paid: ~$71,400. Net Mexican tax: ~$160,000–$210,000. Total: ~$230,000–$310,000.
The timing difference: $130,000–$210,000.
If the sale closes after you've moved but you haven't yet established permanent roots (you're renting, you've kept a US address, no RFC, no Article 4 tiebreaker lost), maintain strong documentation of your US treaty residency position and consider filing Form 8833 to document it explicitly. Consult a cross-border tax attorney before closing if there's any ambiguity.
What You Get in Exchange for Mexican Taxes (Spoiler: Not Much)
Let’s say you did become a Mexican tax resident on $60,000 in US income. You’d pay roughly $13,000 annually to Mexico. What does that buy?
Not IMSS. Voluntary IMSS enrollment for a couple in their 60s costs about $2,000 USD per year separately — and that’s before the exclusions for preexisting conditions, which eliminate most retirees from eligibility in the first place. Hypertension, diabetes, heart disease, cancer history: all grounds for denial.
Not functioning municipal services. Ensenada loses an estimated 30% of its water supply to leaky pipes. Some neighborhoods go three months between service. The beaches have been closed for sewage contamination. The potholes are civic legend.
Not the healthcare system we covered in the universal healthcare post. IMSS-Bienestar left 11+ million prescriptions unfilled in 2024. The Baja California state government spent 200 million pesos of its own money covering federal shortfalls. Families at Hospital General de Tijuana paid out of pocket for NICU tubing.
Mexico collects the lowest tax-to-GDP ratio in the entire 38-country OECD — 18.3% versus the OECD average of 34.1%. The services reflect that. An American retiree paying Mexican ISR would be funding a system that cannot reliably pipe clean water to its own residents.
Why SAT is unlikely to come looking for you anyway
The realistic enforcement risk for a US retiree with 100% US-sourced income, no RFC, and no Mexican bank account is structurally very low. Here's why.
The CRS/FATCA information gap is the most important fact in this analysis. Mexico participates in the OECD's Common Reporting Standard (CRS) and receives automatic financial account data from 120+ countries — but not from the United States. The US operates its own system (FATCA) and is not a CRS participant. Under the reciprocal Model 1 FATCA IGA between the US and Mexico, the US reports to Mexico only very limited data: interest of $10+ on depository accounts of identified Mexican residents. It does not share account balances, capital gains, IRA distributions, brokerage values, or most investment income. Your Schwab account, Fidelity IRA, and Wells Fargo checking are structurally invisible to SAT as long as you maintain a US domicile address.
SAT's enforcement priorities target different taxpayers. SAT's 2026 Master Plan (summarized by Baker McKenzie and CCN Law) focuses on recurrent tax losses, simulated invoice schemes, improper refund claims, tax-haven transactions, and unusually low effective rates relative to industry. These are the signatures of Mexican corporations and high-wealth Mexicans with offshore assets visible through CRS. No public cases exist of SAT pursuing a US retiree with no Mexican-source income, no RFC, and no Mexican bank account.
Documented enforcement against foreigners involves Mexican-source income: unreported Airbnb rental income on vacation properties, undeclared gains on Mexican property sales, unremitted IVA on services physically performed in Mexico. All of these involve a Mexican tax footprint SAT can see. A US-only retiree has no such footprint.
The treaty tiebreaker under Article 4 is also a defensive fallback: even if SAT ever did raise the question, a retiree who has maintained a US permanent home, US banking, US medical care, and US family ties has overwhelming evidence to be treated as a US treaty resident — limiting Mexico to taxing only Mexican-source income, which is zero.
The honest caveat: If you have genuinely abandoned all US ties — sold your home, closed your accounts, cut every US anchor — you're in greyer territory and the technical non-compliance risk is higher. The planning answer is to keep a genuine US home with documentation. That single act converts the analysis from grey to clearly defensible.
The Practical Checklist
This is what actually protects you.
Keep on the US side:
- A real US address — family member’s home is better than a mail-forwarding service for brokerage KYC purposes. Ideally in a no-income-tax state: South Dakota, Texas, Florida, Nevada, Washington, Tennessee, or Wyoming. California, New York, and Virginia are notoriously reluctant to accept that you’ve left and will try to keep taxing you.
- US bank and brokerage accounts. Schwab International and Interactive Brokers are the most expat-friendly. Fidelity works for existing accounts. Vanguard is the most hostile — move assets before you leave.
- US driver’s license and voter registration.
- Medicare Part A and B. Losing Part B is expensive to fix later.
- File Form 1040 every year with your US address.
Avoid on the Mexico side:
- No RFC. This is the single most important don’t. The RFC is Mexico’s tax ID. Getting one creates a SAT file and filing obligations. You don’t need one for most daily life. If a specific transaction (property purchase, formal employment) forces it, get advice first.
- No Mexican bank account. Mexican accounts trigger FATCA reporting, create KYC records listing you as a Mexican resident, and require FBAR/Form 8938 filings above certain thresholds.
- No Mexican-plated vehicle if you’re on Permanent Residency. The Baja Free Zone lets Temporary Residents drive US-plated cars indefinitely. Permanent Residents are technically prohibited from foreign-plated vehicles, and Baja checkpoints began enforcing this in late 2025. This is one of several reasons to stay on Temporary Resident status longer than you think you need to.
- Don’t upgrade to Permanent Residency prematurely. Temporary Resident (renewable up to 4 years, then renewable again) is more compatible with maintaining a credible US-center-of-life argument.
- Rent, don’t buy. A fideicomiso (the trust structure foreigners use to hold coastal property) requires an RFC, creates a permanent-home footprint under Mexican tax law, and is SAT’s most reliable trigger for examining foreigners’ tax residency.
Pay for life in Mexico using:
- Schwab Bank debit card (rebates all global ATM fees)
- Fidelity Cash Management debit
- Wise multi-currency account (UK e-money institution, not a Mexican bank)
- USD cash from border casas de cambio
- US wire transfers for large payments like rent
The One Sentence Version
Keep your financial life in the United States, maintain a real US home, stay off SAT’s radar, and the law — both countries’ law — is on your side.
If you’re selling a US property and moving in the same year, talk to a cross-border tax attorney before you close. That one conversation is worth more than everything else in this post.
This is not legal or tax advice. For readers with Mexican-source income, Mexican property, or a pending US home sale: consult a cross-border tax professional before structuring your affairs. Reputable firms in this space include Procopio, Cacheaux Cavazos, Sanchez-DeVanny, Basham Ritch Mueller, and Chevez Ruiz Zamarripa.
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