Methods
A two-arm, parallel-groups, randomised controlled trial was employed. Both groups received treatment as usual, with the intervention group also receiving a 12-week text messaging intervention. Participants were adult, weekly or more frequent smokers, recruited online and in primary health care centres. Research personnel were blinded, while participants were not. Primary outcomes were prolonged abstinence and point prevalence of abstinence, 3 and 6 months post-randomisation. All randomised participants were included in analyses.