Mariculture is one of the fastest growing global markets. Although it has potential to improve livelihoods and facilitate economic growth, it can negatively impact marine biodiversity. Here we estimate local cumulative environmental impacts from current and future (2050) mariculture production on marine biodiversity (20,013 marine fauna), while accounting for species range shifts under climate change. With strategic planning, the 1.82-fold increase in finfish and 2.36-fold increase in bivalve production needed to meet expected global mariculture demand in 2050 could be achieved with up to a 30.5% decrease in cumulative impact to global marine biodiversity. This is because all future mariculture farms are strategically placed in sea areas with the lowest cumulative impact. Our results reveal where and how much mariculture impacts could change in the coming decades and identify pathways for countries to minimize risks under expansion of mariculture and climate change through strategic planning.