What makes seafarers & mariners different from an ordinary filing?
Ships have their own treaty article, and it usually allocates crew income by reference to the enterprise operating the ship rather than the waters sailed. Days at sea are also treated differently from days in a country for most residency tests. An ordinary preparer applies the general rule and stops there, which is how the relief in the specific provision goes unclaimed.
Can you work with my existing accountant?
That is how most of these engagements run. They keep the domestic file, we take the cross-border piece, and the boundary is agreed in writing so nothing is done twice or missed.
Which country actually taxes my sea pay?
Start with the shipping article rather than the map. It generally allocates crew income by reference to the enterprise operating the ship, so the answer turns on where that enterprise is established, not on the flag the vessel flies and not on the waters it sailed through. Your home country may then tax the same income as a resident, giving relief for what the other country was entitled to charge. So the question is rarely which single country taxes you. It is which one has the primary right, which one taxes you as a resident, and how the second gives credit for the first.
My family stayed home while I sailed, am I still resident there?
In most cases yes, and crew are regularly surprised by it. Residency tests look at where your settled ties are, not simply at how long you were away, and a house and a family left behind are among the strongest ties there are. Time in international waters is generally not presence in any country, so long absences at sea do not build residency somewhere else either. The practical result is that you can owe a resident-basis return at home on worldwide income while owing nothing at all in the country you sailed out of.
Does the flag state get to tax me?
Not usually, and this is the most common misunderstanding in crew files. The flag is a matter of registration. The treaty article that matters allocates crew pay by reference to the enterprise operating the vessel, and operators frequently register ships somewhere they have no establishment at all. A flag state with no operating enterprise and no presence by you generally has no claim on your pay. Where a deduction has nonetheless been taken, the answer is not to accept it as unavoidable but to test the taxing right and, if there is none, to reclaim it where it was taken.
Do I owe tax in the port country where I signed on?
Joining a vessel in a port does not by itself create a liability there. What can create one is an employer or a manning agent established in that country, or a period actually worked ashore there. The distinction matters because payroll systems often deduct on the basis of where the crew member joined rather than on the basis of any taxing right. If the deduction is being taken in a country that has no right to the income, the money is recoverable there, but it is recovered by claim, not by asking the agent to stop.
If two countries both tax me, which one gives the credit?
As a rule the country taxing you as a resident gives relief for the tax the other country was entitled to charge on the same income, not the other way round. Two consequences follow. The first is that the entitlement matters more than the deduction: a credit is given for tax properly charged, so tax deducted without a taxing right is reclaimed at source rather than credited at home. The second is sequence. The primary liability has to be quantified before the credit can be computed, which is why the two returns are prepared together.
Do I owe anything at home if I was at sea all year?
Very possibly. A year spent almost entirely aboard does not remove a home-country filing obligation if you remained resident there, and residency usually survives long absences when the family, the home and the financial ties stay put. What changes is the arithmetic rather than the duty to file. The pay is reported, the treaty allocation is applied, and credit is claimed for tax the other country was entitled to charge. Filing nothing on the basis that you were not in the country is how crew accumulate years that later need a disclosure rather than a return.
I have not filed for several years while living abroad — what are my options?
Both countries have routes back, and using one before they contact you is what preserves the relief. On the US side there are procedures aimed at taxpayers whose failure was not wilful, including one designed for people living outside the country, and separate procedures for late account reports and information returns alone. Canada has its voluntary disclosures programme and taxpayer relief for penalties and interest. Filing quietly and hoping is the one approach with no protection attached to it. See catch-up filing.
How many days can I spend in a country before I become tax resident?
It depends on the country, and a day count is only ever the start. Many use a threshold in a tax year, some also look at averages across several years, and some have no day test at all and decide on where your home and life are. Two countries can both conclude you are resident, which is what the treaty tie-breaker exists to settle. Counting days without checking the tie-breaker is how people end up filing as resident nowhere. See the residency tie-breaker.
