Dependence on seafood imports is growing for many nations, effectively exporting the environmental and social impacts from consuming nations to producers. While countries have commitments to national regulations and global sustainability targets, such as the United Nations Sustainable Development Goals, sustainability standards for imported seafood are lacking. We examine the sustainability implications of high-income countries’ reliance on seafood imports, using Australia as a case study. Australia imports around 60-70% of domestically consumed seafood, with 96.5% imported from 20 countries. Compared to Australia, these countries generally have lower environmental performance, higher vulnerability to slavery, and increased risk of illicit trade in their supply chains. Yet, biophysical limits on wild catch, low demand for underutilized species, social conflict, environmental concerns over aquaculture expansion, and low domestic production, suggest imports will likely remain an important source of seafood for Australian consumers. Other high-income countries in Europe and North America face similar challenges. These countries have a pivotal role in promoting responsible trade. Comprehensive sustainability assessments that integrate environmental and social considerations of production and trade, improved mapping of seafood production activities, and more granular trade data will be critical for informed and effective trade regulations that support sustainability commitments.