Abstract Contemporary young students in Asia and in the Nordic region are increasingly learning English outside the classroom by using technology (a.k.a. Informal Digital Learning of English [IDLE]). This comparative study examines to what extent IDLE influences Korean and Swedish students’ willingness to communicate in a second language (L2 WTC) , a critical antecedent affecting actual L2 communication behaviour. After having achieved a cross‐cultural equivalence of the research instrument, Korean ( n = 388) and Swedish ( n = 144) secondary school students were surveyed. Results of hierarchical regression analyses show that Frequency of IDLE (the total amount of IDLE activities) predicts both cohorts’ L2 WTC, while Receptive IDLE activity (consuming English content) and Productive IDLE activity (producing English content) are predictors for only Koreans’ L2 WTC. Results suggest that Korean and Swedish students tend to more frequently initiate English communication when engaging in IDLE activities. Results also suggest how Receptive and Productive IDLE activities could uniquely facilitate the L2 communication behaviour of Korean EFL learners, who learn English in a linguistically and culturally homogeneous society. Apart from context‐specific pedagogical implications, this study could provide insights for L2 learners worldwide who have been learning language remotely with minimal supervision. Practitioner notes What is already known about this topic Informal Digital Learning of English (IDLE) has been found to be beneficial in Korean and Swedish EFL students’ communication skills and productive vocabulary knowledge. Diversity (a combination of form‐ and meaning‐focused activities), not frequency (amount of time) of IDLE activities, is a significant predictor of Korean learners’ scores on a productive vocabulary test. These results stand in contrast to results found in Sweden that reported a positive relationship between frequency of IDLE activities and productive vocabulary test scores. After having achieved a cross‐cultural equivalence of the questionnaire, this comparative study aims to examine to what extent IDLE influences Korean and Swedish students’ willingness to communicate in a second language (L2 WTC) , which is a critical antecedent affecting actual L2 communication behaviour. What this paper adds Frequency of IDLE predicts both cohorts’ L2 WTC. Receptive (consuming English content) and Productive IDLE activities (producing English content) seem to uniquely facilitate the L2 communication behaviour of Korean EFL learners, who learn English in a linguistically and culturally homogeneous society. Implications for practice and policy Informed by these results, L2 policymakers and teachers can design and implement socio‐culturally and contextually appropriate curricula and pedagogical practices to enhance learners’ L2 WTC and, ultimately, L2 communicative competence. This study also provides insights for L2 learners worldwide who have been learning language remotely, with minimal supervision.