The study aimed to analyse the production of plosive sounds by trilingual speakers of L1 Polish - L2 English - L3 Norwegian. The main objective was to trace any changes in the VOT production of fortis and lenis stops in all three languages (Polish, English and Norwegian) produced by novice L3 learners with a focus on possible cross-linguistic interactions. The investigation was conducted across three testing times throughout the first year of L3 learning. The results show that participants maintained separate VOT patterns in all three languages. What is more, VOT production patterns changed over time, but only in the voiced series of stops. The study also provides evidence for asymmetry between voiced and voiceless stops, as the two series turned out to be affected by CLI in a different manner.