Notice to Mariners vs. Notice to Shipping (Navigational Warnings)

What’s the Difference?

Before heading out, boaters should always tune their VHF radios into the Canadian Coast Guard’s continuous marine broadcast frequency that is applicable in their area so that they can familiarize themselves with any notices to shipping or urgent weather updates that might be available.


A number of boaters use the terms notice to mariners and notice to shipping synonymously. They are quite different.

A notice to mariner is actually a permanent change to a printed chart that should be adjusted by the mariner for safe navigation. For example, if a buoy is being removed permanently, the change will show up in the notices. It is up to the user to correct it on their charts. You might notice when purchasing a chart there may be an update stamped on the chart which includes a date that includes all previous changes.

Notice to shipping is what we are listening for on the continuous marine broadcasts. They are now referred to as navigational warnings and they inform the mariner of any temporary change that the mariner must know about for safe navigation. For example, if a buoy has drifted off-station or its light is extinguished, that temporary change would appear on the navigational warning list.


In addition to tuning the VHF radio into the CMBs before heading out, the Coast Guard has made navigational warnings and notices to mariner available on-line, which is a great help.

They can be found at:
Notices to Mariner:
Navigational Warnings: