The paper focuses on an unexplored area of metalinguistic awareness in the acquisition of third language (L3) phonology, hereafter referred to as metaphonological awareness. It addresses the role of attention and noticing in input processing. The contribution constitutes a part of a larger scale project on metaphonological awareness in various multilingual settings investigated through the application of stimulated recall verbal protocols. The study involved quasi-concurrent retrospective and introspective protocols, in which the participants were asked to attend to, modify, and comment on their phonological output in L3 Polish after listening to an excerpt of their previous text reading recording. The investigation aimed to explore qualitative and quantitative aspects of metaphonological awareness manifested through the participants' self-repair and modifications of pronunciation mistakes in L3 Polish, reflective metalinguistic analysis of their oral performance in L3, intentional focus on articulatory gestures, self-awareness of problems in L3 pronunciation, the level of metacognitive control, and comments on the pronunciation learning process. Explored from a multilingual perspective, the construct of metaphonological awareness was demonstrated to entail an interaction of metalinguistic awareness as well as cross-linguistic awareness and to be an essential component of multilingual competence.