Background An electronic cigarette (e-cigarette) is an electronic nicotine delivering system that may be widely used by smokers in Thailand for some reasons, although e-cigarette is an embargo good in Thailand and their benefits are not clear. Moreover, the behaviors of Thai e-cigarettes users remain insufficient and ambiguous. This study aimed to survey behaviors of using e-cigarettes and rationales among Thai e-cigarette users. Methods We conducted a cross-sectional study from December 2019 to February 2020 throughout Thailand. The participants were Thais with at least 18 years old and currently using e-cigarette, and they were invited to voluntary participate in the study using an online questionnaire posting on social media. Results Of 1,050 participants, most of participants were men (89.1%); the average age was 31.2±8.4 years old. They were from all regions of Thailand, but most of them (64.5%), were from the central part of Thailand. Of currently Thai e-cigarette users, 43.2%, 23.1%, and 14.9% were private employees, business owners/ freelancers, and students, respectively. Most of the users were graduated with a bachelor's degree (53.8%), and Senior high school or Vocational certificate (25.0%). E-cigarette users reported the top 3 rationales for using e-cigarette were the belief of less harmful of e-cigarette than a conventional cigarette (81.0%), using as a smoking quitting aid (80.6%), and lacking attaching normal cigarette odor (58.2%). Conclusions This study shows that most of the e-cigarette users were males with an average age of 31 years old. Smokers used e-cigarette because of the belief of less harmful of e-cigarette than a conventional cigarette and being a quitting aid. The public health organizations and health care providers should provide accurate information and raise awareness of users about the harm of e-cigarettes and inconclusive evidence of using e-cigarettes as a quitting aid. Key messages The public health organizations should provide accurate information and raise awareness of users about the harm of e-cigarettes and inconclusive evidence of using e-cigarettes as a quitting aid. Most of Thai e-cigarette users were men, at the average age of 31 years old, from the central part of Thailand, work as private company employees and bachelor’s degree graduated.

Electronic cigarettes (e-cigarettes) use is trending in Thailand. Electronic cigarettes are banned and illegally imported. This study aimed to investigate the behaviour, rationale, and satisfaction of e-cigarettes users and compared them between males and females. A cross-sectional study was conducted involving 1050 participants using e-cigarettes from December 2019 to February 2020. The participants were recruited by an online questionnaire posted on social media. The participants were current e-cigarettes users aged 18 years and older. Of 1050 participants, 936 were male (89.1%). The average age was 31.2 ± 8.4 years. The participants were from all regions of the country, but most (64.5%) were from central Thailand. Most e-cigarettes users comprised private employees (43.2%). The main source of e-cigarettes in Thailand is online sources such as social media. Tank-style e-cigarettes were popular among users. Amongst e-cigarettes users, the top three rationales for using e-cigarettes were fewer harmful effects from e-cigarettes than conventional cigarettes (81.0%), smoking cessation aids (80.6%), and their lack of attaching cigarette odour (58.2%). The top three reasons for satisfaction were using e-cigarettes as a conventional cigarette cessation aid (5.1 ± 1.3), lessening cravings for conventional cigarettes (5.1 ± 1.3), and reducing conventional cigarettes withdrawal symptoms (5.0 ± 1.3). Online purchase was the main source of e-cigarettes in Thailand. The general rationale for using electronic cigarettes was that they are less harmful and to quit conventional cigarettes. Thai users were satisfied to use e-cigarettes as a conventional cigarette cessation aid. Males and females differed in behaviour, rationale, and satisfaction of e-cigarettes. Public health organisations should provide accurate information about the harm of electronic cigarettes and their efficacy for tobacco cessation.