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Why Seafarers’ Earnings Deduction matters

If you’re a UK resident, Seafarers’ Earnings Deduction can allow you to claim 100% tax relief on your foreign earnings.

This means that under certain conditions your income from working at sea may be exempt from UK income tax, potentially saving you a significant amount. However, qualifying for this deduction requires meeting specific criteria related to your time spent outside the UK.

How to qualify for SED

How to qualify for SED

  • You must work on a ship (not a fixed offshore installation like an oil rig).
  • A legitimate seafarer will have time onboard and time on leave.
  • HMRC assesses your employment over a 365-day “Eligible Period”.
    • The 365-day Eligible Period starts when you first leave the UK to begin work at sea.
    • The Eligible Period can be continuous (365 days out of the UK) or consist of multiple trips, but:
    • There must not be a gap of more than 183 days between foreign trips (i.e. time in the UK must not exceed 183 consecutive days).
    • During the 365-day period, you must have made at least one voyage to a foreign port.
    • Travel days and time in international waters count as time outside the UK.
  • You must be a UK tax resident during the tax year you are claiming for.
  • Only earnings from working on a ship outside UK waters (12-mile limit) are eligible. Only income from working outside UK waters qualifies.

How the calculator works

Our Seafarers Tax Calculator simplifies the criteria listed above by analysing your travel history and applying these rules to determine your potential eligibility for the SED.

Travel dates

We analyse your UK entry and exit dates to calculate the number of days spent working outside the UK.

365 day eligible period

We check whether you’ve worked at sea for 365 days, either in one stretch or over multiple trip.

The half-day rule

You must spend at least twice as long outside the UK as in it – we check this using your travel dates.

SED Calculator

We’ll use your travel history to check if you qualify for the Seafarers’ Earnings Deduction.

 

While we strive to maintain accuracy in the calculator’s functionality, the results are only estimates and are based entirely on the inputs provided by you, the user.

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