Perhentian Island is one of the well-known coral islands in Peninsular Malaysia that attracts a large number of tourists. To create economic returns, the Department of Marine Park Malaysia conserves various aquatic habitats and allows tourists to carry out their water activities. However, most tourists do not have intention of preserving and protecting the natural environment while carrying out their activities. Therefore, this study attempts to explore the moderating effect of environmental facilitating conditions on tourists' environmentally responsible behaviour. For testing the hypotheses, we survey 193 tourists on Perhentian Island. Our results provide two notable findings. First, environmental facilitating conditions moderate the relationship between environmental attitude and their environmentally responsible behaviour. Second, the environmental subjective norm is found to have a stronger direct effect on their environmentally responsible behaviour. This implies that government agencies and local authorities should provide favourable facilitating conditions to encourage tourists to be more environmentally responsible.