Does Mexico use a 183-day tax residency test?

No. For individuals, Mexico has no 183-day rule. You're a Mexican tax resident if your home (casa habitación) is in Mexico; if you also have a home abroad, residency turns on your center of vital interests — more than 50% of your calendar-year income from Mexican sources, or your main professional activity being in Mexico.

Am I a Spanish tax resident if I stayed under 183 days?

Maybe. Spain makes you resident if ANY of three tests is met: more than 183 days in the calendar year, the main base of your economic interests is in Spain, or your non-separated spouse and dependent minor children live in Spain. You can be resident on the last two even with few days.

Myth vs. fact · MX & ES 2026

Am I a tax resident of Mexico or Spain?

Q: What if I'm a resident of both countries?

The Spain–Mexico tax treaty tie-breaker decides, in order: permanent home, center of vital interests, habitual abode, nationality, then mutual agreement between the tax authorities.

"I spent fewer than 183 days, so I'm not a tax resident." Often wrong. Mexico has no 183-day test at all — it's about your home and center of vital interests. And Spain makes you resident on any of three tests — days, economic base, or where your family lives. Check your likely status before it surprises you at tax time.

Check your residency

Which country are you checking?

Days physically in Spain this calendar year

Is the main base of your economic activities or interests in Spain?

Do your non-separated spouse and/or dependent minor children habitually live in Spain?

Your likely status (domestic law)

Which tests apply

How residency is decided & data sources

Mexico (CFF Art. 9). You're a tax resident when your casa habitación (home) is in Mexico. If you have a home in Mexico and another country, residency turns on your center of vital interests — which is in Mexico when more than 50% of your calendar-year income has a Mexican source, or your main professional activity is in Mexico. There is no 183-day test for individuals. Mexican nationals are presumed resident unless they prove residence in another country (a notice/aviso is due within 15 days of ceasing residency).

Spain (LIRPF Art. 9). You're a tax resident if any one of three tests is met: (1) more than 183 days in Spanish territory during the calendar year — and sporadic absences count toward the 183 unless you prove tax residence in another country; (2) the main base of your economic activities or interests is in Spain; or (3) the presumption that applies when your non-legally-separated spouse and dependent minor children habitually live in Spain (rebuttable). Spanish residency is all-or-nothing for the calendar year — no split-year. (New residents may be able to elect the "Beckham" regime, Art. 93, to be taxed as a non-resident on Spanish-source income for up to 6 years.)

If you're resident of both under domestic law, the Spain–Mexico tax treaty tie-breaker decides in order: permanent home → center of vital interests → habitual abode → nationality → mutual agreement.

✅ Rules verified as of July 19, 2026 — Mexico CFF Art. 9 (SAT); Spain LIRPF (Ley 35/2006) Art. 9 (AEAT); Spain–Mexico treaty Art. 4 (BOE) · Domestic-law indicator, not tax advice.

Sources: Mexico — Código Fiscal de la Federación, Art. 9 · Spain — AEAT residencia habitual (LIRPF Art. 9) · Spain–Mexico treaty (BOE), Art. 4

Frequently asked questions

I stayed under 183 days in Mexico — am I safe?

Day count isn't the test in Mexico. If your home is in Mexico (and not more strongly abroad), you can be a Mexican tax resident regardless of days. The "183 days" idea is borrowed from other countries and doesn't apply here.

Can Spain tax me if I barely spent time there?

Yes, potentially — if the main base of your economic interests is in Spain, or if your spouse and minor children live there, you can be resident even under 183 days. Any one test is enough.

What does being a tax resident mean?

Tax residents are generally taxed on their worldwide income by that country, not just local income. That's why the determination matters so much.

What if I qualify in both countries?

You don't get taxed twice with no relief — the Spain–Mexico treaty tie-breaker assigns you to one country for treaty purposes, and foreign tax credits address overlap. But you should get professional advice for a dual-residency year.