International regulations (STCW-95) prescribe that a seafarer sailing aboard a vessel flying the flag of the Netherlands possesses a Dutch Certificate of Competency. 
The Netherlands issues officers from other EU member states and countries with which it has concluded an agreement, a Dutch Certificate of Competency on the basis of their own national Certificate of Competency. 
Ratings may apply for a regular Certificate of Competency. 

• A Certificate of equivalent Competency may only be issued to officers who possess a valid STCW 95 'certificate of competency' issued in a country with whom the Netherlands has concluded an agreement to accept seafarers! 
• For information concerning countries with which the Netherlands has concluded such a bilateral agreement, you should contact the department that issues these Certificates of equivalent Competency.  
• A Dutch Certificate of equivalent Competency (and seaman's book) is not compulsory for foreign ratings, provided you do possess a national Certificate of equivalent Competency and seaman's book.