The purpose of this paper is to analyse tourist's awareness of biosecurity measures in Ireland. The author's recognised tourist vectoring from outdoor recreation can increase the risk of Invasive Alien Species (IAS) and disease in destinations worldwide. The resulting control and eradication are expensive and often unsuccessful. The author's position in this issue contends that future biosecurity risk management strategies at national and local planning levels should incorporate specific tourist awareness and communication programmes that reflect international and European regulation. A mixed methodology was utilised for this research. A theoretical framework was developed which incorporates various components that emerged from the literature to examine outdoor recreational tourist's awareness of biosecurity in Ireland. Combined with findings from a recent study of national-level biosecurity, content analysis was conducted on all Local Authority county development plans (CDP) in Ireland using specific tourist awareness and communication criteria. A survey was distributed among tourists that combined quantitative and qualitative data collection from tourists who participated in outdoor recreational activities. The findings indicate a shortfall in the provision of specific tourism biosecurity awareness and communication at both national and local levels in Ireland. This was reflected in the significantly low level of biosecurity awareness among outdoor recreational tourists in Ireland. This represents a substantial environmental and economic threat to Ireland's sustainability as a nature-based destination. These findings have implications for tourism managers and policymakers to implement evidence-based tourist awareness and communication programmes in Ireland and other nature-based destinations before a biosecurity breach occurs.