Invasive species are generally introduced into an ecosystem as the intended or unintended consequence of economic activity. While there are many studies available examining the costs and benefits of programmes for the control of particular weeds, pests and pathogens, there are in comparison very few studies examining the economics of biological invasions. This is all the more surprising given that these invasive species can impose significant costs on society. Apart from assessing the costs, economics also has a role to play in terms of the control of invasive species. Effective control of invasions depends on using the right economic instruments. Since the risks of invasions into an ecosystem tend to be low but the potential costs high, the costs tend not to be reflected in market prices. Also, the control of potential invasive species is a public good where there will be a tendency of underprovision by the market. The purpose of this paper is to present an overview of the potential economic impacts of invasive species in Irish waters and to discuss the economic instruments that could be used in the prevention, eradication, and control of such species.