Abstract Although the International Maritime Organization (IMO) introduced the energy efficiency requirements for ships more than a decade ago, to date, inland navigation has not been affected by corresponding regulations at all. Therefore, inland waterway vessels are left with no mandatory requirements that could push their technology into more energy efficient design. Fortunately, there are certain pioneering attempts to define energy efficiency criteria for inland vessels. This paper tries to gather and provide a review of such methods. Moreover, a typical Danube cargo inland vessel’s data are used to evaluate their current energy efficiency levels with respect to provisional criteria. Consequently, two methods are found and used here. They are both based on IMO’s energy efficiency concept but modified for the inland waterway vessels. The methods delivered a significant difference in applicability and were difficult to compare. Moreover, shallow and deep-water effects are explored in the same regard but provided unsound conclusions. The final results displayed discrepancies in energy efficiency levels for the same vessels and so the methodology should be improved and harmonised, if it is to be introduced as mandatory for inland waterway vessels. The analysis provided a glimpse into the current condition of the traditional design of the Danube inland fleet, with respect to the emerging energy efficiency policies.