Although storm petrels are regarded as surface feeders, there is evidence that some species can dive. However, their diving performances and the importance of diving in their foraging tactics have never been accurately assessed. This study aimed to determine the occurrence of diving behavior and the diving ability of the Madeiran Storm Petrel (Oceanodroma castro) using maximum depth gauges. Out of 29 gauges deployed, 18 were recovered and 16 were readable. All the birds had dived, the maximum depths recorded averaging 0.85 m, and diving is part of the typical foraging behavior of the Madeiran Storm Petrel. This study provides a new insight on storm petrel foraging strategies.