Notices to Mariners are issued by DMAR as the primary means for promulgating information pertaining to safety and security; the establishment of changes to, and deficiencies in aids to navigation; dangers and hazards to navigation; anchorage; restricted areas; proposed construction or modification of berths; interpretation of regulations; and practical recommendations to assist operators and authorities in their compliance with regulations.

They are numbered sequentially by year with subsequent revisions being identified by a revision number. Notices to Mariners are to be complied with, as applicable, by all parties to which they apply.