This study investigates the practices and perceptions of teachers using social networking sites (SNSs) for informal continuing professional learning in Vietnam. The paper describes one part of a larger exploratory sequential mixed-methods study and draws on data collected via four focus group interviews of 19 EFL teachers from five provinces of southern Vietnam. The study's findings reveal a variety of activities conducted on SNSs for professional learning purposes. These are categorised into four themes: (1) searching, acquiring and sharing resources; (2) offering and seeking academic assistance; (3) improving English proficiency; and (4) connecting and networking. The findings show that most teachers recognise the value of SNSs in terms of usefulness, diversity, flexibility, feeling connected, getting motivated for positive change and cost-effectiveness. This research adds meaningfully to the currently modest literature on how teachers with limited resources, particularly in developing countries, make use of available and affordable digital tools for their own continuing professional learning.