An expiring STCW certificate, CoC, CoP, medical, or visa is one of the most preventable causes of an unscheduled sign-off. Most certificates run on five-year cycles under the 2010 Manila Amendments + flag-state regulations; medicals run on two-year cycles. The right move is not 'wait until it expires'. It is 'plan the renewal before the next contract'.
STCW Regulation I/11 (Revalidation of certificates) + 2010 Manila Amendments. STCW Code Section A-I/11 (proof of continued professional competence). MLC 2006 Regulation 1.3 (Training and qualifications). Flag-state legislation governs the practical revalidation process — see /stcw/country-guides for per-flag detail.
Disclaimer. General information only — final requirements rest with the flag-state administration and the employer. Always verify the refresher provider's approval status before booking.