Do adults learn the same syntactic second language (L2) form explicitly and implicitly simultaneously during meaning-based exposure, and does the type of learning (explicit and/or implicit) affect subsequent performance. In this study, 81 anglophones completed comprehension tasks providing incidental exposure to a semi-artificial language (English lexis, German syntax). A surprise grammaticality-judgement test (GJT) measured performance with the novel syntax. Source attributions and verbal reports provided information on type of learning (implicit and/or explicit), which were analysed in an exploratory fashion to classify within-participant implicit and explicit learning. Sixty-three participants demonstrated both types of learning, which suggests that extant binary classifications of type of learning may be inadequate. Furthermore, there were no significant performance differences on the GJT based on type of learning despite poor performance overall. The interpretation of the findings considers within-participant explicit and implicit learning measures and research issues when comparing the effectiveness of initial explicit learning and implicit learning on immediate performance.