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Third Officer Jobs

1 open vacancy · updated 15 Oct 2026

About the role

A Third Officer (Third Mate, 3/O) is a deck officer who keeps a navigational watch on seagoing ships of 500 gross tonnage or more. The officer fixes the ship's position, monitors radar and traffic, and adjusts course as directed by the voyage plan. On some ships, the Third Officer also takes care of lifeboats, life rafts, fire extinguishers and other safety gear. The rank works on container ships, bulk carriers, tankers, Ro-Ro vessels and other cargo ships. The Third Officer works with the Master, Chief Officer, Second Officer, ABs and OS in bridge and deck operations. The officer may also handle radio duties when assigned.

Duties on board

  • Keep a safe navigational watch on the bridge on ships of 500 gross tonnage or more.
  • Fix the ship's position with GPS, radar, ECDIS and visual bearings.
  • Monitor vessel traffic and use the Rules of the Road to avoid collision.
  • Record courses, positions, weather and bridge orders in the deck logbook.
  • Check lifeboats, life rafts, life jackets and fire extinguishers as part of the onboard safety routine.
  • Assist the Chief Officer with cargo watches during loading and unloading.
  • Perform GMDSS radio watch and communication duties if assigned.
  • Take part in emergency drills for fire, abandon ship and security as required.

Requirements

DocumentConventionNote
Certificate of Competency (CoC) - Officer in charge of a navigational watch on ships of 500 GT or moreSTCW II/1Every officer in charge of a navigational watch on a seagoing ship of 500 gross tonnage or more must hold a certificate of competency.
Basic Training (BST) - STCW VI/1STCW VI/1Seafarers must receive safety familiarization and basic training or instruction.
GMDSS radio operator certificate (if performing radio duties)STCW IV/2Every person performing radio duties on a ship required to participate in the GMDSS must hold an appropriate GMDSS certificate.

Sea service

Approved seagoing service of not less than 12 months as part of an approved training programme documented in a training record book, or otherwise approved seagoing service of not less than 36 months. During that service, the candidate must perform bridge watchkeeping duties under the supervision of the Master or a qualified officer for not less than six months.

Medical fitness

Before beginning work, a Third Officer must hold a valid medical certificate. The certificate confirms satisfactory hearing, sight and, where relevant to the work, colour vision. The certificate is valid for a maximum of two years.

Documents

  • Passport
  • Seaman's book (CDC)
  • Certificate of Competency (CoC) for ships of 500 GT or more
  • Medical certificate
  • Basic Training certificate (STCW VI/1)
  • GMDSS radio operator certificate if assigned radio duties
  • Visas when the flag or port state requires them

Career path

Comes from: Fourth Officer, Junior Officer (Trainee Officer), Deck Cadet
Next step: Second Officer

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Third Officer: questions and answers

What certificate do I need to work as a Third Officer?

You need a Certificate of Competency as officer in charge of a navigational watch on ships of 500 gross tonnage or more under STCW II/1. You must be at least 18 years old, complete approved education and training, and meet the standard of competence required by STCW II/1. You also need basic training under STCW VI/1.

How much sea service is required for a Third Officer CoC?

You need approved seagoing service of not less than 12 months as part of an approved training programme documented in a training record book, or otherwise not less than 36 months. During that service, you must perform bridge watchkeeping duties under the supervision of the Master or a qualified officer for not less than six months.

Does a Third Officer need a GMDSS radio certificate?

It depends on your duties. If you perform radio duties on a ship required to participate in the GMDSS, you must hold an appropriate GMDSS certificate under STCW IV/2. STCW II/1 requires a candidate to meet the designated radio duties requirements, as appropriate.

What is the minimum age to become a Third Officer?

Under STCW II/1, a candidate must be not less than 18 years of age. You must also meet the medical fitness requirements under MLC 2006 Reg. 1.2, which require a valid medical certificate before beginning work on a ship.

Can a Third Officer work on any ship size?

The Third Officer certificate under STCW II/1 is valid for seagoing ships of 500 GT or more. On ships of less than 500 GT engaged on near-coastal voyages, STCW II/3 requires a CoC. On ships of less than 500 GT not engaged on near-coastal voyages, the officer of the watch must hold the certificate for 500 GT or more.
9,400+ Third Officer profiles on Krew Guru · 1 vacancy in the last 90 days

Sources

Checked against the official texts on 26 Oct 2026.