The western swamp turtle (Pseudemydura umbrina) is a Critically Endangered species threatened by climate change. Using an energetically-informed mechanistic niche model, current habitat and five potential translocation sites were assessed for their ability to support survival, growth, and reproduction under future (2050, 2070) southwestern Australian climates. Behavioural flexibility is critical to the suitability of these locations. Increased basking appears to mitigate the reduced hydroperiods expected within their current range, and to offset the cooler conditions likely to be experienced at assisted migration locations. However, it also increases predation risk. This trade-off raises new questions for the species' future management.