Our recent work explores key drivers of global ocean surface wave variability on the sub-seasonal timescale, including their role for promoting high and low wave conditions, with a focus on the Australian marine environment. This talk will highlight the influences of the Madden-Julian Oscillation, the Southern Annular Mode, and split-flow blocking on ocean wave variability and extremes. Their signature extends beyond local wind-generated forcing to remote forcing of surface waves in the North Pacific and North Atlantic oceans. Considering the ability of global climate model forecasts to skilfully predict the SAM and blocking indices out to at least two weeks lead time and the MJO index out to at least four weeks, our results point to each of these drivers as possible sources of predictable wind-wave variability from sub-weekly to seasonal timescales.