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Certificate of competency, certificate of proficiency, endorsement: what each STCW document proves
By the Docka team · Reviewed 7 September 2026
Last updated:
A certificate of competency (CoC) proves a seafarer may serve in a rank. A certificate of proficiency (CoP) proves they completed a specific training. A flag state endorsement proves that a particular flag accepts the CoC for service on its ships. The GMDSS radio certificate and the medical certificate prove something narrower still.
Below: what each document is, who issues it, and how you check it.
Certificate of competency (CoC)
A CoC is issued by a flag state administration under chapters II (deck), III (engine) and IV (radio) of the STCW Convention, which was adopted in 1978 and has been in force since 1984.
It names the capacity the holder may serve in (master, chief mate, officer in charge of a navigational watch, chief engineer and so on) and any limitations, such as tonnage or trading area. It carries a unique number and a date of expiry.
Who issues it: the administration whose examination the seafarer passed. The Maritime and Coastguard Agency (MCA) in the United Kingdom, Søfartsstyrelsen (the Danish Maritime Authority), Sjøfartsdirektoratet (the Norwegian Maritime Authority) and Transpordiamet (the Estonian Transport Administration) all issue CoCs, and all four run a public register for them.
How it is verified: against that register, by certificate number and usually the holder's date of birth. The paper is a copy; the register is the record. Docka runs this check live and automatically for eight flag states and takes you to the official portal for the rest.
What Docka cannot do is confirm a CoC from an administration with no online register. There, the check is an email to the administration, and it takes days.
Certificate of proficiency (CoP)
A CoP proves completion of a specific training or a specific competence, not the right to hold a rank. The common ones are basic safety training (STCW Code section A-VI/1), proficiency in survival craft and rescue boats (A-VI/2), advanced fire fighting (A-VI/3), medical first aid and medical care (A-VI/4), security training (A-VI/6), and the tanker cargo certificates under chapter V.
Who issues it: either the administration itself or a training centre it has approved, acting under the administration's authority. This is where verification gets uneven. A CoP that the administration issued or recorded appears in its register. A CoP printed by a training centre often does not. Paris MoU guidance to inspectors also notes that a CoP does not have to carry an expiry date, although many do.
How it is verified: check the flag state register first. If the CoP is not there, ask the training centre directly, and ask the administration whether that centre is on its approved list. We think a CoP that no register and no centre will confirm should be treated as unverified, whatever the paper looks like.
Flag state endorsement
An endorsement is a flag state's statement about a CoC, and there are two kinds. An endorsement attesting issue is added by the administration that issued the CoC (STCW Article VI and regulation I/2). An endorsement attesting recognition is issued by a different flag state under regulation I/10 when it accepts a foreign CoC for service on its ships.
The second kind is what people usually mean by "flag state endorsement". It is what a Cypriot, Liberian or Panamanian ship needs before a Danish-certificated officer can sign on.
The endorsement can be printed on the CoC itself or issued as a separate document. A separately issued endorsement must carry its own expiry date, which cannot be more than five years from issue and can never run past the expiry of the CoC it endorses. An endorsement expires the moment the underlying CoC expires or is suspended, cancelled or withdrawn.
So "the endorsement is still valid" says nothing on its own. Check the CoC first.
While a recognition endorsement is being processed, a flag state may let the seafarer serve for up to three months on documentary proof that the application was submitted. Inspectors call this the confirmation of receipt of application (CRA).
Verify an endorsement against the register of the flag that issued the endorsement, not the flag that issued the CoC. Those are two different registers.
GMDSS radio certificates
The general operator's certificate (GOC) and restricted operator's certificate (ROC) come under chapter IV of the Convention and are issued by the administration, in some countries through its telecoms regulator, not its maritime authority.
On most ships the deck officers hold the GOC, so the radio certificate is checked alongside the CoC. A watch with no certificated GMDSS radio operator is one of the worked examples of a detainable deficiency in Paris MoU inspection guidance.
Verification follows the CoC path: number and holder against the issuing body's register. Where a different body issued the radio certificate, expect a second register, or none.
Medical certificate
The medical fitness certificate is required by STCW regulation I/9 and is issued by a doctor the administration has approved, not by the administration itself.
In the United Kingdom that is the ENG 1, issued by an MCA-approved doctor, with a maximum examination fee of 115 GBP. If it expires during a voyage, the seafarer may keep working until the next port where it can be replaced, or for up to 3 months after expiry, whichever is sooner.
Verification is the weak spot of the whole set. Medical certificates are rarely in a public register, so the check is with the issuing doctor or against the administration's published list of approved doctors. Docka records the medical and its expiry and reminds you before it lapses. It does not verify a medical against a register unless the flag state publishes one.
The confusions we see most
- "STCW certificate" used to mean the basic safety training CoP. There is no single STCW certificate. A seafarer holds a CoC, several CoPs and often an endorsement, all under STCW.
- An endorsement filed as if it were the CoC. It only says a flag accepts the CoC; without the CoC register check, nothing has been verified.
- A valid-looking endorsement on an expired CoC: impossible by rule, so nobody checked the endorsement against the CoC.
- The GMDSS certificate assumed to be part of the deck CoC. It is a separate document with its own number and often its own register.
- The medical treated as verified because the PDF looks right. Call the doctor.
Who issues what, and where to check
| Document | Issued by | Where to check |
|---|---|---|
| Certificate of competency | Flag state administration | The administration's register, by number and date of birth |
| Certificate of proficiency | Administration or an approved training centre | The register if recorded there; otherwise the centre |
| Endorsement (recognition) | The recognising flag state | That flag state's register, not the CoC issuer's |
| GMDSS GOC or ROC | Administration or its telecoms regulator | The issuing body's register, where one exists |
| Medical (ENG 1 and equivalents) | A doctor approved by the administration | The issuing doctor; the approved-doctor list |
Frequently asked questions
- Is a certificate of proficiency the same as a certificate of competency?
- No. A certificate of competency (CoC) entitles the holder to serve in a named capacity, such as chief mate or second engineer. A certificate of proficiency (CoP) confirms completion of a specific training, such as basic safety training or advanced fire fighting. An officer holds one CoC and several CoPs; a rating usually holds CoPs only.
- Does a flag state endorsement expire when the CoC expires?
- Yes, at the same moment. Paris MoU inspection guidance states that an endorsement expires as soon as the certificate it endorses expires or is suspended, cancelled or withdrawn. A separately issued endorsement also carries its own expiry date, which may not run past the CoC.
- Can Docka verify a certificate issued by a training centre?
- Only when the flag state records that certificate in the register it publishes. Docka checks flag-state registers, not training-centre databases. A CoP that appears nowhere in the administration's register has to be confirmed with the centre that printed it, and Docka will show it as unverified until you do.
Sources
- IMO: the STCW Convention, chapters, 1978 adoption, 1984 entry into force.
- Paris MoU: PSCC instruction 57/2024/05, endorsement and expiry rules.
- GOV.UK: seafarer medical certificates, the ENG 1 rules.
- Registers named above: United Kingdom (coccec.mcga.gov.uk), Denmark (verify.dma.dk), Norway (verify.certificate.sdir.no), Estonia (meremees.transpordiamet.ee).
Which registers Docka checks live, and what each one asks for, is on the registry coverage page. The method behind every check is in how seafarer certificate verification works.
Check a certificate now, free
Enter the certificate number and Docka checks it against the issuing flag state's register.
Check a certificate now, free