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HMRC internal manual

Tonnage Tax Manual

Qualifying companies and ships: Seagoing ship


In order to qualify for tonnage tax a ship must be ‘certificated for navigation at sea by the competent authority of any country or territory’ – FA00/SCH22/PARA19 (4).

There are two important points to note:

  • The ship must be certificated to operate at sea at the time it is in use
  • The certification must cover the normal commercial operation of the ship (see below).

If a ship is not ‘certificated for navigation at sea’ then it does not qualify for tonnage tax.  This applies even if the appropriate competent authority would have certificated the ship had they been approached.

The relevant certificate or certificates can not be backdated.  If a ship is resurveyed and, as a result, receives a certificate that enables it to qualify for tonnage tax, then that ship can only qualify from the date of re-certification.  This applies even where no modifications to the ship have had to be undertaken to obtain the new certificate.

‘Normal Commercial Operations’

In order to qualify for tonnage tax, the ship must be certificated for navigation at sea and its normal commercial operations must be at sea.

For example if a temporary certificate is issued to enable a ship to be sailed from the builder’s yard in Spain for delivery to the shipping company on the Thames, where it is used within the confines of the Thames estuary, then that ship is not certificated as seagoing when it is performing its normal commercial operations.

A ship will not be certificated for navigation at sea if the certificate does not cover the full year operation of the ship.

There is additional guidance on what is a seagoing ship:

TTM03515 Certification
TTM03520 Restricted certificates

TTM03520 deals with some particular certification issues.


For further details of the types of certificates issued under both international conventions and domestic legislation and the effect of restrictions in those certificates as regards the waters to be sailed in, see TTM03520.


FA00/SCH22/PARA19 (qualifying ships) TTM17101
Contact points TTM01120