Introduced marine organisms continue to threaten coastal resources around the world. Many agencies rely on lists of potentially harmful species for risk assessment and to prioritise management responses to an incursion. This study outlines a deductive hazard assessment technique to identify potential marine pests that may arrive via ballast water and/or hull fouling. This technique is then applied in an Australian context to identify potential "next pests" for this region. An extensive literature review identified 851 introduced marine species from around the world. The following selection criteria were then applied to develop a next pest list: (a) the species has been reported in a shipping vector or has a ship-mediated invasion history; (b) the vector still exists; (c) the species is responsible for economic or environmental harm; and, (d) it is exotic to Australia or present in Australia but subject to official control. The selection criteria are transparent and consistent with other international and national biosecurity initiatives. Thirty three of the species identified in the initial literature review satisfied all four selection criteria. These species are described here together with their associated vectors and impacts.