The aim of this study was to determine sex work practices and predictors of condom use among female sex workers (SWs) in Sydney. SWs from two centres completed a self-administered questionnaire covering demographic and sexual characteristics and sex work practices. One hundred and forty-eight international (born in Asia) and 141 local SWs (born in Australia, New Zealand or the UK) were recruited. Local SWs saw more clients per shift than international SWs (P=0.002), but international SWs worked more shifts per week than local SWs (P=0.001). International SWs used condoms less consistently at work than local SWs (P=0.001). About 37% of international SWs never used condoms with non-paying partners, compared with 14% of local SWs (P=0.01). Speaking Thai (odds ratio [OR] 8.9, 95% confidence interval [CI]; 3.19–24.87) or Chinese (OR 17.4; 95% CI 4.98–60.89) (both P<0.001) and previous sex work in Thailand (OR 10.0 95% CI 2.31–43.52; P=0.02) were associated with inconsistent condom use. Strategies to improve condom use need to be evaluated.