This study aims to investigate the nature of phonological awareness in young L3 learners, and the extent to which it changes over time as L2 and L3 learning progresses. Two groups of 12 closely matched multilinguals (total= 24, aged 12-13), who shared their L2 (English) but their L1/L3 (German/Polish) were mirrored, mimicked L2 and L3 accents in their L1 speech and reflected over their mimicry performance at the beginning and at the end of the first year of L3 instruction. Based on both quantitative and qualitative analyses, the results showed a differentiated range of manifestations of phonological awareness in the two groups of young multilinguals, possibly explicable by the phonological distance of their L2 and L3 in relation to their L1. No significant changes in the learners' L2/L3 phonological awareness were detected over the school year. In addition, combined group results showed a moderate correlation for the learners' L2 mimicry and foreign accent ratings at both testing times and for their L3 mimicry and foreign accent ratings at the second testing. Insights gained from individual phonological awareness profiles suggest, however, that this relationship may not hold for all L3 learners. The findings are also discussed from a methodological perspective.