US State Taxes After Moving to Spain: How to Break State Residency

Federal income tax follows a U.S. citizen anywhere, and most people planning a move know it. State income tax after moving to Spain is the layer they miss, because it follows something less visible: domicile. A state that considers you domiciled there keeps taxing your worldwide income, Spanish salary included, with no credit for Spanish tax and no room for the treaty. California and New York publish detailed tests and audit against them. This guide sets out what each asks, what a domicile change requires, and how Spanish residency overlaps with both. This article is for informational purposes only and is not immigration, tax or medical advice; verify current requirements with the relevant Spanish authority or a licensed professional.

Why does a move to Spain not end your state tax by itself?

Because both states define residency around intent, and intent is presumed to continue until you prove otherwise. The California Franchise Tax Board states in its residency guidelines that a resident of California continues to be a resident when absent from the state for a temporary or transitory purpose, and that once you acquire a domicile you retain it until you acquire another. New York’s income tax definitions say the same thing in different words: your New York domicile does not change until you can demonstrate that you have abandoned it and established a new domicile outside New York State.

Two features of the California rules make the state layer more expensive than people expect. The Franchise Tax Board states that California allows neither a foreign tax credit nor a foreign earned income exclusion, so the Spanish income tax you pay does nothing for the California return. It also states that tax treaties between the United States and other countries which expressly limit their application to federal income taxes do not apply to California. A person who is a Spanish tax resident and a California resident in the same year pays both, on the same salary, without relief.

The Spanish test is different and runs on its own. The Agencia Tributaria treats you as a Spanish tax resident for a calendar year in which you spend more than 183 days in Spain, or in which the main base of your economic interests is there, and it presumes residence when your spouse and dependent minor children live in Spain. Nothing in that test speaks to a U.S. state, and nothing in the state tests speaks to Spain. The overlap is yours to close.

The two tests, state by state

Each state runs two tests, and passing one is not enough: a domicile test built on intent and facts, and a mechanical test built on days and a dwelling.

California: closest connections, and the Spain example the FTB itself gives

The Franchise Tax Board’s Publication 1031 states the theory in one sentence: you are a resident of the place where you have the closest connections. It then lists the factors it uses, from the time you spend in and out of the state to the location of your spouse and children, your principal residence, the state that issued your driver’s license and registered your vehicles, where you hold professional licenses and vote, where your banks, doctors, accountants and attorneys are, and where your real property and investments sit. The publication states that it is the strength of the ties, not just the number, that determines residency, and that no one factor is determinative.

The same publication gives an example that could have been written for this site. Example 5 of its section on leaving California describes a person who accepts a permanent job offer in Spain, sells the California home, packs everything, moves to Spain with spouse and children on May 5, 2025, leases an apartment, enrolls the children in school, obtains a Spanish driver’s license and has no intention of returning. The determination: a part-year resident, a California resident through May 4 and a nonresident from May 5, taxed by California on all income while resident and only on California-source income afterward.

The examples around it show what fails. A person who declares Nevada residency but keeps the California home, spends six or seven months a year in it and keeps the social club and business connections remains a California resident, because the declaration establishes nothing and the connections do. A person on a 15-month assignment abroad who keeps a California driver’s license, voter registration and bank accounts, and lives in an employer’s compound, remains a resident, because the ties established abroad are thinner than the ties kept in California.

What a change of domicile requires

The publication defines domicile as the place where you voluntarily establish yourself and your family, not for a special or limited purpose but with a present intention of making it your true, fixed, permanent home, the place you intend to return to whenever you are absent. It states that the maintenance of a marital abode in California is a significant factor in establishing California domicile, and that a change of domicile requires all three of the following: abandonment of the prior domicile, physically moving to and residing in the new locality, and intent to remain there permanently or indefinitely, as demonstrated by your actions.

Actions, not declarations. That is why the Spain example lists a sold home, a leased apartment, a school enrollment and a Spanish driver’s license rather than a signed statement.

The safe harbor, and who it leaves out

The safe harbor is narrower than its reputation. It covers a person domiciled in California who is outside the state under an employment-related contract for an uninterrupted period of at least 546 consecutive days. Return visits totaling 45 days or fewer in a taxable year are treated as temporary. The safe harbor is lost if intangible income exceeds $200,000 in any taxable year the contract covers, or if the principal purpose of the absence is to avoid personal income tax. The spouse who accompanies the employee for at least 546 consecutive days is also treated as a nonresident.

Two things follow. The days of two separate contracts cannot be combined: the publication’s own example of a one-year contract, three months back in California and a second one-year contract fails the test. And a retiree, a remote worker without a contract, or anyone moving on a non-lucrative visa is outside the safe harbor entirely and is judged on the closest connections facts instead.

New York: the permanent place of abode trap

New York’s definitions make you a resident on either of two grounds. The first is domicile: the place you intend to have as your permanent home and return to after being away. The second needs no intent at all. If you maintain a permanent place of abode in New York State for substantially all of the taxable year and spend 184 days or more in the state during that year, you are a resident whether or not you are domiciled there for any part of it, and any part of a day counts as a day.

A permanent place of abode is a residence you permanently maintain, whether or not you own it, that is suitable for year-round use, and it usually includes a residence your spouse owns or leases. A vacation structure not suitable for year-round use is not one, and neither is a barracks or a place kept only during a temporary duty assignment. An apartment kept in the city for visits home is.

The two exceptions for a New York domiciliary

New York also states two groups of conditions under which a person still domiciled in New York is not treated as a resident, and both are built for people abroad. Group A: no permanent place of abode in New York during the year, a permanent place of abode outside New York for the entire year, and 30 days or fewer in New York. Group B: at least 450 days in a foreign country during any period of 548 consecutive days, 90 days or fewer in New York during that 548-day period for you, your spouse (unless legally separated) and your minor children together, and a prorated limit for the partial tax years in which the 548-day period begins and ends, computed as the number of days in the nonresident portion divided by 548 and multiplied by 90.

Group B is the one that fits a move to Spain with a kept apartment, and it is arithmetic. Ninety days across a year and a half, counting the family, with a day log to prove it.

What the state still taxes after you leave

Breaking residency ends tax on your worldwide income, not on income the state considers its own. Publication 1031 states that nonresidents of California are taxed only on income from California sources, and it sources income by type.

• Wages have their source where the services are performed, so remote work done from Spain for a California employer is not California-source, while days worked in California on a visit are.
• Gain on real estate has its source where the property is located: a California home sold after you move to Spain is taxable by California even though you are a nonresident. The federal exclusion and the Spanish treatment are in selling your U.S. home after moving to Spain.
• Pensions and retirement accounts point the other way. The publication states that nonresidents are not taxed by California on pensions received after December 31, 1995, and that IRA, Roth IRA, SIMPLE IRA, SEP and Keogh distributions received after becoming a nonresident are likewise not taxable if received after that date. Timing a withdrawal before or after the departure date is therefore a state tax decision, not only a federal one.
• Interest, dividends and gains on stocks and bonds generally have their source where you are a resident, so they leave the state with you, with an exception for accounts used in a California trade or business.

For the year of the move, the publication describes a part-year return on Form 540NR that reports all income while resident and California-source income afterward, with the tax computed at the effective rate that would apply to your income from all sources. The departure date on that return is the single fact everything else hangs on.

The Spanish side: two residencies can overlap in the year you move

Spain does not split a year. If you exceed 183 days in Spain during the calendar year of your arrival, the Agencia Tributaria treats you as a Spanish tax resident for that whole year, and it presumes you are resident when your spouse, not legally separated, and your dependent minor children live in Spain, unless you prove otherwise. A person who leaves California on May 5 and stays in Spain is a California resident through May 4 and a Spanish resident for all of that year.

That overlap is unavoidable in the arrival year and it is manageable, because the two systems tax different periods once the domicile change holds: California through the departure date, Spain for the year, and the U.S.-Spain treaty and the foreign tax credit sort out the federal layer. What is not manageable is an overlap that repeats every year because the state never accepted the departure. The practical consequences of Spanish residency, from Modelo 720 to the FBAR that follows you, are in the mistakes Americans make when moving to Spain.

The steps that hold up, in the order to take them

1. Fix a departure date and build the file around it. Every test above turns on when the ties were cut. Keep the lease, the sale documents and the flight in one folder.
2. Deal with the home first. A retained California residence is on the FTB’s list of factors and a kept New York apartment is a permanent place of abode. Sell it, or lease it out on terms that show you cannot use it, before you leave.
3. Move the civic ties. Driver’s license, vehicle registration, voter registration and professional licenses are four of the FTB’s factors. A Spanish driver’s license is in the FTB’s own Spain example.
4. Move the financial and professional ties. The location of your banks, the origination point of your transactions, and the location of your accountants and attorneys are on the same list.
5. Keep a day log from the day you leave. New York counts any part of a day; California weighs time in and out of the state. A calendar with boarding passes attached is the cheapest audit defense there is.
6. File a clean part-year return for the year of the move. In California that is Form 540NR with the departure date and only income through that date, plus California-source income afterward.
7. Check what still flows from the old state. Rental income from a kept property or a sale of real estate stays taxable there on a nonresident basis, so plan for a nonresident return in later years if that applies.

Book the domicile change before you book the flight

Write down the date you will leave and list every tie you still hold in your state on that date: home, license, registration, accounts, advisers, memberships. Each item on that list is a fact the state can weigh against you, and each one you close before the departure date becomes a fact for you.

Someone leaving a state with no personal income tax, or leaving a cooperative state with no home kept, no business interest and no plan to return, can usually handle this alone with the state’s own residency page and a part-year return. Someone leaving California or New York with a home kept, a business or professional license, high investment income, or family staying behind is in the territory the audit programs are built for, and a state tax professional who handles residency cases should read the file before the move rather than after the first notice.

The Spain Navigator, the app that puts every step of your move to Spain in order, keeps the departure date, the state file and the Spanish registrations of your first month in one plan, so the ties you cut on one side line up with the ones you create on the other.