US-Mexico Dual Citizenship: Eligibility, Taxes, and Passports

You can hold US and Mexican dual citizenship at the same time. Both governments allow it: the United States has recognized dual nationality through Supreme Court rulings and State Department policy for decades, and Mexico formally opened the door in a constitutional amendment that took effect on March 20, 1998.¹ Holding both passports gives you the right to live, work, own property, and vote in either country. It also means each country’s tax, travel, and legal rules apply to you separately.

How You Qualify

Birth in Either Country

A child born on US soil is a US citizen at birth under the Fourteenth Amendment, regardless of the parents’ nationality, with a narrow exception for children of foreign diplomats.² Mexico’s constitution works the same way: anyone born in Mexican territory is Mexican by birth.³ A baby born in the US to Mexican parents is a dual citizen from day one.

Descent From a Citizen Parent

You don’t have to be born in either country to claim citizenship in it. A child born outside the US to at least one US citizen parent can acquire American citizenship at birth if the citizen parent lived in the US for a required period beforehand; the exact residency rule depends on whether one or both parents are citizens and when the child was born.⁴ On the Mexican side, anyone born abroad to at least one Mexican parent is Mexican by birth.¹

Naturalization

A Mexican citizen can naturalize in the US through USCIS, and a US citizen can naturalize in Mexico through the Secretaría de Relaciones Exteriores. In both cases you keep your original citizenship. The US naturalization oath contains language about renouncing allegiance to foreign states, but it functions as a statement of loyalty to the US, not a legal mechanism that strips your other nationality.⁵ Mexico does not treat the US oath as causing loss of Mexican nationality for anyone who is Mexican by birth.³

Reclaiming Mexican Nationality

If you were born in Mexico and naturalized in the US before March 20, 1998, you likely lost your Mexican nationality under the old rules. You can reclaim it through the Declaratoria de Nacionalidad Mexicana at a Mexican consulate. You’ll need your Mexican birth certificate, a certified and apostilled copy of your US naturalization certificate with a Spanish translation, a government-issued photo ID, and a passport-sized photo. There is a processing fee, and no appointment is required.⁶

What Mexican Citizenship Gets You

Property in the Restricted Zone

Mexico’s constitution bars foreigners from directly owning land within 50 kilometers of the coastline or 100 kilometers of an international border. That strip, called the restricted zone, covers Cancún, Los Cabos, Puerto Vallarta, Tijuana, and much of the country’s most desirable real estate.⁷

If you hold Mexican nationality, you can own property directly anywhere in Mexico, restricted zone included. A US citizen without Mexican nationality who wants a beachfront home has to set up a bank trust (fideicomiso), which runs roughly $500 to $600 per year in administration fees and requires a renewable 50-year permit from the Secretaría de Relaciones Exteriores. A dual citizen skips that structure entirely.

Voting in Both Countries

You can vote in US federal, state, and local elections as a US citizen and register to vote in Mexican elections as a Mexican national. Mexico has allowed citizens abroad to vote in presidential elections since 2006, handled through the National Electoral Institute. Voting in a foreign election will not put your US citizenship at risk.⁸

What Dual Citizenship Blocks You From in Mexico

Certain Mexican offices are reserved for citizens by birth who hold no other nationality. The presidency, seats in Congress, Supreme Court judgeships, and senior military positions all fall within this restriction, and additional federal laws extend it to other public roles. If you want to hold one of these offices, you’d generally need to renounce your US citizenship first.³

Traveling With Two Passports

US law requires you to enter and leave the United States on your US passport. You cannot enter on a foreign passport even if it would otherwise be valid.⁹ Mexico may require you to use your Mexican passport for entry and departure.¹⁰ Carry both, and use each at the appropriate border.

One boundary worth flagging: a dual-national child under 18 traveling into or out of Mexico without at least one parent needs a notarized consent letter from both parents or legal guardians specifying the means of travel, destination, and dates. A letter notarized outside Mexico must carry an apostille stamp and a Spanish translation. A child traveling with at least one parent does not need the authorization.

Taxes and Foreign Account Reporting

This is the area where dual citizenship generates the most ongoing paperwork. The United States taxes its citizens on worldwide income, so a dual citizen living and earning in Guadalajara still files a US return each year reporting that income.¹¹

Three mechanisms keep you from paying full taxes to both countries on the same income:

The Foreign Earned Income Exclusion lets you exclude up to $132,900 of foreign earned income from US taxes in tax year 2026, if you meet the bona fide residence test or the physical presence test.¹²
The Foreign Tax Credit generally lets you credit Mexican income taxes against your US liability, though not every foreign tax qualifies.
The US-Mexico income tax convention provides specific rules to relieve double taxation when a US citizen resides in Mexico, including which country’s credits apply first.¹³

FBAR and FATCA

Two separate reporting rules cover your Mexican financial accounts, and they overlap without substituting for each other. The FBAR (FinCEN Form 114) is triggered when the combined value of your foreign financial accounts exceeds $10,000 at any point during the year, and it’s filed with FinCEN, not with your tax return. Penalties for failing to file can be severe even for non-willful violations.¹⁴

FATCA reporting on IRS Form 8938 has higher thresholds. If you live in the US, you file when foreign assets exceed $50,000 at year-end or $75,000 at any point during the year, doubled for joint filers. If you live abroad, the thresholds rise to $200,000 at year-end or $300,000 at any point for individual filers, and $400,000 or $600,000 for joint filers.¹⁵ You may owe both filings.

Social Security

The US and Mexico do not have a totalization agreement, the type of bilateral pact that keeps workers from paying social security taxes to both systems at once.¹⁶ If you work in Mexico and also have US-covered earnings, such as self-employment income, you may contribute to both systems without the streamlined coordination that agreements with Canada and the UK provide. A cross-border tax professional earns their fee here.

The Limit on Consular Protection

When you are physically in Mexico, your US citizenship may not help you as much as you’d expect. Under widely accepted principles of international law, when a dual national is in one of their countries of citizenship, that country has the primary claim. The State Department will attempt to intervene, but Mexico is not obligated to accept those representations.⁸

In practice, if you are arrested or detained in Mexico, authorities may treat you exclusively as a Mexican national and deny US consular access. The State Department’s own manual warns that consular assistance “may be limited” and that the receiving state may not recognize the US as entitled to provide consular services at all. The same principle works in reverse: Mexico’s ability to help you inside the United States may be similarly limited.

Losing Citizenship on Either Side

Losing US citizenship is difficult unless you want to lose it. The Supreme Court held in Afroyim v. Rusk that Congress cannot strip a person of citizenship without voluntary consent, and Vance v. Terrazas requires the government to prove both a specific expatriating act and the person’s intent to give up citizenship.¹⁷ Becoming a Mexican citizen, voting in Mexican elections, or serving in Mexico’s government does not cost you US citizenship unless you intended it to.

On the Mexican side, the rules split by how you got your nationality. Mexicans by birth (born in Mexico, on a Mexican vessel, or abroad to at least one Mexican parent) cannot be stripped of their nationality no matter how many other citizenships they acquire. Mexicans by naturalization can lose it by voluntarily acquiring a foreign citizenship, using a foreign passport while claiming to be a foreigner, or living outside Mexico for five consecutive years.¹

1
Law Library of Congress. Mexico Law on Dual Nationality
2
Office of the Law Revision Counsel. 8 USC 1401 – Nationals and Citizens of United States at Birth
3
Secretaría de Relaciones Exteriores. Double Nationality
4
U.S. Citizenship and Immigration Services. I Am the Child of a US Citizen
5
U.S. Citizenship and Immigration Services. USCIS Policy Manual – The Oath of Allegiance
6
Consulado General de México en Houston. Declaratoria de Nacionalidad Mexicana por Nacimiento
7
Consulado de México en el Reino Unido. Acquisition of Properties in Mexico
8
U.S. Department of State Foreign Affairs Manual. 7 FAM 080 Dual Nationality
9
U.S. Department of State. Dual Nationality
10
U.S. Embassy and Consulates in Mexico. Dual Nationality
11
Internal Revenue Service. Publication 54 – Tax Guide for US Citizens and Resident Aliens Abroad
12
Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026
13
Internal Revenue Service. United States – Mexico Income Tax Convention
14
FinCEN. Report Foreign Bank and Financial Accounts
15
Internal Revenue Service. Do I Need to File Form 8938, Statement of Specified Foreign Financial Assets
16
Social Security Administration. US International Social Security Agreements
17
Office of the Law Revision Counsel. 8 US Code 1481 – Loss of Nationality by Native-Born or Naturalized Citizen