Prior research has shown the challenges associated with establishing novel perceptual categories for L2 segments that differ from those in the native segmental inventory of L2 English learners. Further investigation is needed to understand how L2 segments that serve as allophones in learners’ L1 phonological systems are acquired. The present study, therefore, aims to contribute to the literature by investigating how successfully L1 Turkish speakers perceive the English phoneme /w/ which is reported to manifest as an allophone in the Turkish language. To this end, ten individuals with L1 Turkish and two individuals with L1 English backgrounds participated in a pair of perception tests, each spanning 15 to 20 minutes: a discrimination test and an identification test. The findings indicated that Turkish learners of L2 English could identify the /w/ phoneme with an accuracy rate exceeding 60% in both tasks, particularly excelling in novel phonemic contexts presented in the identification task. Qualitative analysis of the interviews with successful participants revealed key factors contributing to their successful acquisition of the English /w/ sound. Participants highlighted the importance of exposure to L2 English, access to authentic input sources, opportunities for meaningful communication, intrinsic motivation, availability of diverse teaching resources, and integration of technology in autonomous pronunciation learning endeavors. This study enhances our understanding of the perceptual acquisition of L2 segments that function as allophones in the learner’s L1 highlighting the plasticity of L2 perceptual learning. It also emphasizes a holistic approach to L2 phonological acquisition, offering practical implications for language instruction and autonomous learning.