Despite the fact that the majority of teenagers and young adults use smartphones, little research has studied English Learners’ (ELs’) actual mobile phone language practices, specifically, how and why ELs use their smartphones as language learning assistant devices (Godwin-Jones, 2008). The primary purpose of this qualitative study was to explore ELs’ perceptions of mobile-assisted language and literacy practices, and to document ELs’ literacy practices through their mobile devices. Drawing from New Literacies Studies (Gee, 2004, 2010; Kress, 2003), research questions that guided this study were as follows: 1) How do participants use mobile devices in their classes, and what features of mobile devices do they find useful (e.g., recordings, video, still photo, etc.)? 2) What mobile device applications do participants find important in school and/or in their everyday lives? 3) Is there a relationship between participants’ use of mobile devices and their identity in and out of school? Participants were four ELs aged from 15 to 21: Three high school students and one university student. Primary data for this study were semi-structured interviews collected over a three-month period. Data were analyzed using constant comparison, looking across participant interviews to generate themes. Several important findings emerged. First, participants utilized various applications/features for language learning, and their mobile device practices were inextricably linked to their social practices through their use of mobile phones. Second, participants intentionally used mobile devices as tools to translate, capture class notes, and seek out auxiliary materials to support their learning in school. Third, ELs’ reported that their transition from their home country to the US, resulted in a shift in their personality and identity and their mobile devices provided an emotional support. This study extends current literature and explains how mobile devices play an essential role in ELs’ lives in and out of school. With increasing EL populations in US schools, this study articulates ELs’ actual use of mobile devices, and how mobile devices are important to ELs’ success in the classroom.