Conservation volunteer tourism (VT) (or nature conservation expedition)-related organisations can provide a meeting point for both tourists and field-based scientists. Expedition leaders should be aware of the needs of the volunteer tourists that can be fulfilled through VT. It appears that the role of expedition leaders is central to the successful execution of the VT expedition. This study aimed to understand the expedition leaders' perceptions of VT, their perspective of the expectations of their volunteer tourists and their requirements of the volunteers, and assess how volunteers perform with regard to those requirements. The results suggest that there may be some differences in perceptions between leaders and volunteer tourists that may affect the success of the expedition. Copyright © 2008 John Wiley & Sons, Ltd.