In several studies it is highlighted that the early acquisition of a language in the home results in phonetic and phonological benefits, and that it is not uncommon for early learners to achieve native-like pronunciation in their heritage language. However, most of these studies have been carried out with bilinguals. The present contribution aims at extending the research focus to trilingual teens, and more specifically to Spanish heritage speakers (HSs), schooled mainly in English, and taking part in a French immersion programme. How do they manage the task of learning a third phonological system? We set out to explore whether and to what extent these sequential trilinguals can produce native-like speech in all of their languages. To this end, we recorded a group of Spanish HSs while completing three picture-naming tasks (in English, Spanish, and French), which led to the production of monosyllabic and disyllabic words with a voiceless stop in stressed onset position. Our results show that they tend to produce monolingual-like stops in their dominant languages, Spanish and English, but seem to fail to do so in French. In our discussion, we resort to language dominance and context of acquisition to shed light on our findings.