An extensive number of studies acknowledge the transformed nature of literacies by building on the complexity of multimodal semiotic repertoires and available digital resources (Reinhardt & Thorne, 2019; Toffoli, 2020). The exposure to such resources and tools makes digital literacies dynamic as environments provide students with opportunities to apply their skills in praxis through trial and failure. Among the existing conceptual constructs that might help discuss the complex nature of online digital informal learning practices and their connection to L2 digital literacies, the framework of dynamic systems theory (Larsen-Freeman, 2019) is implemented. Qualitative methodology was employed to explain whether informal language learning practices are conducive to constructing L2 digital literacies among pre-service language teachers. Relevant pedagogical implications are discussed. [For the complete volume, "CALL and Professionalisation: Short Papers from EUROCALL 2021 (29th, Online, August 26-27, 2021)," see ED616972.]