The present study examines whether and to what degree providing explicit phonetic information (EI) at the beginning of form-focused instruction (FFI) on second language pronunciation can enhance the generalizability and magnitude of FFI effectiveness by increasing learners' ability to notice a new phone. Participants were 49 Japanese learners of English in English as a foreign language setting. Whereas the control group (n = 14) received meaning-oriented lessons without any focus on form, the experimental groups received 4 hr of FFI treatment designed to encourage them to practice the target feature of an English /[vd (post)alveolar approximant]/ in meaningful discourse. Instructors provided EI (i.e., multiple exposure to an exaggerated model pronunciation of /[vd (post)alveolar approximant]/ and rule presentation on the relevant articulatory configurations) to the FFI+EI group (n = 17) but not to the FFI-only group (n = 18). Their pre- and posttest performance was acoustically analyzed according to various lexical, task, and following vowel conditions. The results of the ANOVAs showed that (a) the FFI-only group demonstrated moderate improvement with medium effects (e.g., change from hybrid exemplars to poor exemplars), particularly in familiar lexical contexts, and (b) the FFI+EI group not only demonstrated considerable improvement with large effects (e.g., change from hybrid exemplars to good exemplars) but also generalized the instructional gains to unfamiliar lexical contexts beyond the instructional materials.