A method and system for planning the journey of a submarine are provided using at least one electrical drive with a battery for energy supply and a charging device for the battery. For a selected future point in time, the remaining available energy reserve of the battery is predicted on the basis of the travel duration up to this point in time, of at least of one consumption profile selected for the travel duration, and of the type and duration of the charging cycles of the battery being effected up to this point in time.