Question 1

Who qualifies for the Seafarers' Earnings Deduction (SED)?

Accepted Answer

HMRC allows you to claim the SED if you are an employee who worked on a ship, spent enough time outside the UK to build up an eligible period and were resident in the UK or another European Economic Area (EEA) state for tax purposes.  An eligible period usually requires at least 365 days during which you were absent from the UK at midnight on most days and you did not spend too much time in the UK.  You must have at least one voyage that begins or ends at a foreign port.  You cannot claim if you were a Crown employee (for example Royal Navy) or if you are neither a UK nor an EEA resident. However, Royal Fleet Auxiliary personnel are civilian employees and may claim if they meet the other conditions.

Question 2

What counts as a ship for SED purposes?

Accepted Answer

For SED you must work on a vessel that is capable of navigation; offshore installations such as oil rigs, wind farms and fixed production platforms do not count.

Question 3

How long do I need to be outside the UK?

Accepted Answer

To build an eligible period you must usually be absent from the UK for at least 365 days.  A combined period is acceptable provided the intervening UK period (Period B) must be 183 days or fewer, and you must have more than half your days outside the UK.  Each qualifying day is one where you are outside the UK’s 12‑mile territorial limit at midnight.

Question 4

Do holidays abroad count towards my 365 days?

Accepted Answer

Yes.  HMRC’s rules count any day spent abroad at midnight as a qualifying day, even if you were on holiday rather than working.  There is no statutory limit on how many holidays you can include when building up your eligible period; what matters is the total number of qualifying days outside the UK.

Question 5

Do training courses or college attendance count?

Accepted Answer

No.  The deduction only applies to earnings for duties performed onboard a qualifying vessel.  While attending college or other shore‑based training you are not performing duties onboard, so those earnings cannot be claimed.  You may, however, be able to maintain an ongoing claim by taking holidays abroad at appropriate times while at college, but always speak to a tax professional for your specific situation.

Question 6

Do dry‑dock or stand‑by days count?

Accepted Answer

Time spent on a ship in dry dock may still be counted as vessel service.  When standing by a new build abroad, your days out of the UK can help build the eligible period, but you cannot claim the deduction against earnings while standing by because you are not performing duties onboard until sea trials start.

Question 7

Does working on an offshore installation qualify?

Accepted Answer

No.  Fixed installations such as oil rigs, FPSOs, wind farms or flotels are not considered ships for the purposes of SED, so earnings from these do not qualify.

Question 8

What counts as being outside the UK?

Accepted Answer

A day outside the UK is one where you are absent at midnight.  HMRC usually requires you to be beyond the 12‑mile territorial limit.  When a ship sails from one UK port to another UK port, it must be outside the 12‑mile limit at midnight for that day to qualify.

Question 9

Which locations count as ‘abroad’ for leave days?

Accepted Answer

The Channel Islands, the Isle of Man and the Republic of Ireland count as outside the UK for SED purposes.  HMRC expects robust evidence of your travel, especially when you stay close to the UK.  Plan to travel far enough from the border to obtain proof of being out of the UK and keep boarding passes and receipts to support your claim.

Question 10

What records do I need to keep?

Accepted Answer

HMRC may check your claim, so keep a completed working sheet HS205, air tickets or travel vouchers, hotel bills or receipts, passports and visas, your seafarer’s discharge book and freeboard logs of the ships you served on.  Keeping these records helps prove your periods of absence and the ships on which you worked.

Question 11

How do I prove a holiday or time abroad?

Accepted Answer

HMRC does not give a precise list of acceptable evidence.   Provide at least travel tickets to show your dates of travel and ideally bank or credit‑card statements showing transactions abroad.  The burden is on you to prove your time out of the UK.

Question 12

How do I claim the Seafarers' Earnings Deduction?

Accepted Answer

If you are UK‑resident, register for Self Assessment and complete a tax return including the ships you worked on.  If you are resident in an EEA country but not the UK, you may claim using form R43M(SED).  You must make your claim within four years of the end of the relevant tax year.

Question 13

When do I need to submit my tax return?

Accepted Answer

Self‑Assessment tax returns must be submitted by 31 January following the end of the tax year.  The claim itself must be made within four years of the end of the tax year, e.g. by 5 April 2028 for the 2023/24 tax year.

Question 14

What are the time limits for back‑dated claims?

Accepted Answer

You generally have four years from the end of the tax year to claim the SED.  HMRC’s guidance lists specific deadlines; for example, claims for the 2018/19 tax year (ending 5 April 2019) must be made by 5 April 2023.

Question 15

Do I still pay National Insurance if I qualify for SED?

Accepted Answer

Yes.  Even if you owe no income tax because of SED, you usually still have to make National Insurance contributions.  Your residency and domicile status will determine the exact position.

Question 16

Will having another job in the UK affect my claim?

Accepted Answer

SED eligibility depends on qualifying ship duties and the eligible-period tests (days/Period B/foreign port). Having a second job doesn't by itself invalidate SED, but you must declare all income on your tax return as it can affect your overall tax liability.

Question 17

Can I claim if I am resident outside the UK but within the EEA?

Accepted Answer

Yes.  Following an EU ruling, anyone resident in an EU or EEA country can claim SED in the same way as a UK resident.  You must still call at a foreign port and spend sufficient time out of the UK, and be prepared to prove your periods of absence.

Question 18

Does leave taken after a qualifying period count as qualifying days?

Accepted Answer

No.  The eligible period is calculated solely from the dates you leave and return to the UK.  Leave taken after a claim cannot be used to extend the period.  Speak to a tax professional for advice on this.

Question 19

Does the anniversary date of my claim matter?

Accepted Answer

No.  There is no requirement to be outside the UK on the anniversary of starting your claim.  The only rule is that a new claim must span at least 365 days and you must not spend too much time in the UK between absences.

Question 20

When is a ship no longer regarded as a ship for SED?

Accepted Answer

Units whose function is not navigation (e.g., FPSOs) are not ships for SED.

Question 21

How does Seadays help me track eligibility?

Accepted Answer

Seadays is a mobile and web app designed specifically for UK seafarers.  It allows you to log your trips abroad, record your days in and out of the UK, see your progress toward the 365‑day requirement, and receive notifications when you are approaching the half‑rule limits.  Using Seadays alongside the HMRC working sheet and keeping evidence of your travel can help you stay on top of your SED claim.  While the app offers guidance, we always recommend consulting a professional tax adviser for personalised advice.

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