Notices to Mariners (NTM) inform mariners of important matters affecting navigational safety including new hydrographic information such as, changes in depths, obstructions to avoid, dangerous areas to transit, aids to navigation, and other important data. Notices to Mariners are used to amend a vessel's nautical charts and publications portfolio to ensure a vessel is sailing with the most accurate and reliable navigation data. Application of the latest Notices to Mariners to a vessel's nautical charts and publications portfolio is required in order to be in full compliance with regulation of the revised Chapter V of the Safety of Life at Sea (SOLAS) Convention and U.S. §33 CFR 164.33



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United States

The U.S. Notices to Mariners are produced and made available weekly by the National Geospatial-Intelligence Agency (NGA) in conjunction with the National Ocean Service (NOS) and the U.S. Coast Guard. The information in the U.S. Notices to Mariners (NTM) is formatted to simplify the correction of nautical paper charts, List of Lights, Light Lists, United States Coast Pilots, and other publications produced by NGA, NOS, and the U.S. Coast Guard.

Navigation information for the U.S. Notice to Mariners is contributed by the National Geospatial-Intelligence Agency (Department of Defense) for waters outside the territorial limits of the United States; National Ocean Service (National Oceanic and Atmospheric Administration, Department of Commerce), which is charged with surveying and charting the coasts and harbors of the United States and its territories; the U.S. Coast Guard (Department of Homeland Security) which is responsible for the safety of life at sea and the establishment and operation of aids to navigation; and the Army Corps of Engineers (Department of Defense), which is charged with the improvement of rivers and harbors of the United States. In addition, important contributions are made by foreign hydrographic offices and cooperating observers of all nationalities.

The U.S. Notice to Mariners consist of a page of Hydrograms listing important notations such as, a chart correction section organized by ascending chart number, a product catalog corrections section, a publications correction section, a summary of broadcast navigation warnings, and a page of additional miscellaneous information. It is the responsibility of mariners to decide which of their charts and publications require corrections. Mariners are requested to cooperate in the correction of charts and publications by reporting all discrepancies between published information and conditions actually observed and by recommending appropriate improvements. A reporting form is provided in the back of each Notice to Mariners.

Issue No. 1 of each year contains important information on a variety of subjects which supplements information not usually found on charts and in navigational publications. This information is published as Special Notice to Mariners Paragraphs. Additional items considered of interest to the mariner are also included in this Notice.

The U.S. goverment has also put out the unclassified Summary of Corrections publications which contain a reiterative compilation of all U.S. chart and publications corrections (less USCG Light Lists, NIMA List of Lights, and NIMA Hydrographic Catalog corrections) published against the current edition of each individual product originally issued in the Notice to Mariners. 

Five separate volumes of the Summary of Corrections, organized by regions of the world, are published on an annual basis. Volumes 1-4 contain corrections to regionally numbered charts and Volume 5 contains corrections to world and ocean basin charts and corrections to navigational publications.


United Kingdom

Admiralty Weekly Notice to Mariners (NMs) are produced by the United Kingdom Hydrographic Office (UKHO) for the purpose of providing corrections and updates for all Admiralty nautical charts and publications for foreign and domestic vessel use. 

Admiralty Nautical Charts and Publications should be maintained so that they are updated to the latest corrections and amendments. The Admiralty Weekly Notices to Mariners assists in providing necessary navigation information mariners need to confidently and safely navigate their intended voyage. 

In addition to the Admiralty Weekly Notice to Mariners the UKHO produces the Cumulative List of Admiralty Notices to Mariners and Annual Summary of Notices to Mariners. The Cumulative List of Admiralty Notices to Mariners (NP234 A/B) assists users who wish to identify outstanding NMs and audit trails for a particular chart or charts. The list is published annually, with Part A in January and Part B in July. To supplement Weekly NMs, the UKHO produces an Annual Summary of Notices to Mariners (NP247). This publication contains the Annual Statutory Notices to Mariners Numbers 1-26, a summary of Temporary and Preliminary Notices to Mariners still in force at the start of the year, and a Cumulative Summary of Amendments to Admiralty Sailing Directions.

The UKHO also provides support publications like NP294 - 'How To Keep Your Admiralty Products Up-To-Date and NP133A - 'Paper Chart Maintenance Record'. NP294 provides specific guidance on how to apply the corrections contained within NMs to Admiralty Charts. NP133A enables mariners to keep a neat and formal record of all the NMs applied to a vessel's portfolio of charts.