The unsustainable use of irrigation water is one of the most serious environmental problems in coffee farming. Rapid expansion of sustainability certifications and adoption of advanced irrigation technologies are expected to promote more sustainable water use through changes in water management practices in coffee farming. However, there lacks empirical evidence on the effects of those certification schemes on water efficiency. This study examines the effect of sustainability certification on the water efficiency of coffee growers, considering distinct irrigation technologies used by farmers - overhead sprinkler and micro-basin irrigation technologies. The meta-frontier framework is used in our empirical analysis of 896 Vietnamese coffee farms over three crop years. Results confirm that irrigation water efficiency in coffee farming is substantially low. There is no evidence supporting the effect of sustainability certification on water efficiency, but advanced irrigation technologies could improve water efficiency. Coffee farms using the sprinkler system are more efficient than those using the micro-basin irrigation technology. Our results also support environmentally friendly farming practices, i.e., having wind-break trees on coffee farms. It also suggests that improving the quality of sustainability certification schemes towards sustainable use of water requires water-saving technologies.