Sydney Rock Oysters (SRO, Saccostrea glomerata) are endemic to NSW and are extensively cultivated on Australia’s east coast. When farmed, SROs are regularly emersed for drying - an anti-fouling process where oysters are removed from the water for consecutive days to desiccate biofouling organisms. However, drying can lead to oyster mortality, highlighting our lack of understanding of SRO responses to emersion. This study aims to determine how commercial SROs respond to drying regimes. SROs of varying size (<5mm - >30mm width) were exposed to a range of temperatures (20oC-40oC) in replicate air chambers under laboratory conditions for up to 12 days. This was then repeated using changing diurnal temperature gradients with predetermined highs and lows based on environmental temperature data collected in Wallis Lake, NSW, a prominent oyster growing estuary. Daily subsamples were assessed to determine mortality rates for different temperature gradients and samples collected for metabolomic analysis to assess sub-lethal stress. Higher temperatures increased likelihood of mortality with an underlying size effect which suggests risk to stock under current drying regimes. SROs are NSW’s most valuable fisheries product, and this information will be used to develop models to allow farmers to maximise production in the future.