This study seeks to empirically explore the relation between multilingual learning experiences and language aptitude. Through employing LLAMA aptitude test battery (Meara, 2005) and a probabilistic version of the serial reaction time (SRT) task (Kaufman et al., 2010), scores from 24 Chinese-English bilinguals and 24 Tibetan-Chinese-English trilinguals were analyzed with One-way Analyses of Variance (ANOVA). LLAMA-B, E, and F sub-tests measured explicit language aptitude, while LLAMA-D sub-test and SRT task measured implicit language aptitude, a cutting-edge that has gained sway in aptitude research. Qualitative and quantitative results showed that trilingual group performed better on the LLAMA-E sub-test than bilingual group, whereas bilingual group outperformed trilingual group on the SRT task. These findings suggested that trilinguals might possess higher explicit aptitude but lower implicit aptitude than bilinguals. Thus, prior language learning experiences might be positively (for explicit aptitude) or negatively (for implicit aptitude) correlated with language aptitude. Additionally, explicit aptitude and implicit aptitude might have a competitive relationship. Possible implications were discussed in this article.