The GMDSS maintainer may also be the person designated to have primary responsibility for radio - communications during Distress incidents if licensed as an operator.

Ships must carry at least two persons who qualify as a GMDSS maintainer for the maintenance and repair of equipment if the at-sea maintenance option is selected.

All at-sea maintenance and repairs must be performed by, or under the supervision of a person holding a GMDSS Maintainer license or GMDSS Operator license.

The GMDSS maintainer may not be the person responsible for ensuring that the watches are properly maintained and that the proper guard channels and the vessel's position are entered into the DSC equipment.