BackgroundThe hardening hypothesis proposes that as smoking rates decline, the remaining smokers will become hardcore and resistant to quitting. This group of highly resistant quitters will potentially require more individualistic approaches to cessation and harm reduction. The harm reduction approach (specifically e-cigarettes) has been proposed as an option to address hardened Australian smokers. We tested the hardening hypothesis by analysing the rates of hardcore smoking in the Australian smoking population between 2010 and 2016. MethodsData were drawn from three waves of the National Drug Strategy Household Survey (NDSHS) in 2010, 2013 and 2016. Two different definitions were used to assess hardcore smoking to arrive at an upper and lower rate. Logistic regression models assessed hardcore smoker characteristics for both definitions of hardcore smoking. ResultsThe most inclusive definition of hardcore smoking (i.e., a smoker with no plan to quit) showed a significant decline in hardcore smoking between 2010 and 2016 (5.49%–4.85%) In contrast, the prevalence of hardcore smoking using the most stringent definition (i.e., a current daily smoker of at least 15 cigarettes per day, aged 26 years or over, with no intention to quit, a lifetime consumption of at least 100 cigarettes, and no quit attempt in the past 12 months) did not change significantly between 2010 and 2016. ConclusionThe observed trends in the prevalence of hardcore smokers (i.e., either stable or declining depending on the definition) suggest that the Australian smoking population is not hardening. These results do not support claims that remaining smokers are becoming hardcore.