The Mariner Exam Modernization Act seeks to significantly update the process for developing and administering the Merchant Mariner Credentialing Examination. It amends existing law to expand the responsibilities and composition of the examination working group , requiring them to assess the relevancy of exam questions, content, and industry standards. Key changes include extending the timeframe for establishing the working group and adding individuals who have recently passed the exam to its membership. The bill mandates that the working group convene annually or when new questions are created, and it prohibits the use of new exam questions until they have been reviewed and approved by this group. Furthermore, the Commandant must conduct a comprehensive review of the examination, considering industry practices and technology, and then develop a plan to update and modernize the exam within 270 days. This plan must address the elimination of outdated topics, the modernization of testing procedures, and the implementation of data collection methods for future analysis. The Commandant is also required to brief congressional committees on the review and modernization plan within one year of the Act's enactment.