Merchant Mariner Credentials Improvement Act of 2007

Merchant Mariner Credentials Improvement Act of 2007 - Revises requirements with respect to merchant mariner's documents, licenses, and certificates of registry to authorize the advanced renewal of such items which shall not be valid until the date that the originally issued items expire.

Prohibits the Secretary of the department in which the Coast Guard is operating from charging a fee for the application, processing, or issuance of a merchant mariner's document if, within 30 days of the date the individual submits a complete application for the document, the Secretary has not: (1) issued the document to the individual; or (2) notified the individual that the document will not be issued because the individual does not meet certain qualifications.

Prohibits the Secretary from requiring an individual to be fingerprinted for the issuance or renewal of a merchant mariner's document, license, or certificate of registry if the individual was previously fingerprinted upon applying for a transportation security card.

Extends an expiring merchant mariner's document, license, or certificate of registry for one year (currently, such items are issued for a five-year period with renewals for additional five-year periods) to help eliminate a backlog in processing such items.

Requires the Secretary to develop an interim clearance process for issuance of merchant mariner's documents to help newly hired seamen who do not pose a safety and security risk to begin working on an offshore supply vessel or towing vessel.

Requires the Secretary to report to Congress on: (1) a plan to ensure that the application process for a merchant mariner document can be completed entirely by mail; and (2) the feasibility of the redesign of such document to comply with certain standards.