The aim of this study was to investigate how the smartphone users perceive and use smartphones as English learning tools. 79 college students majoring in English language & literature participated in the research. The major research methods were student questionnaire and focused interview. Statistical analysis of the questionnaire was conducted. The research results showed that the most frequent usage of smartphones for English learning was searching online dictionary and using free smartphone vocabulary learning applications. However, despite the great advantages of the smartphone as a learning tool, a number of students do not feel comfortable in using the smartphone for learning purposes due to the environment that the smartphone is used which does not ensure duration and concentration of learning. Other limitations that smartphones have as a language learning tool were discussed. Because of these limitations, 67.1% of the students showed no intention to purchase the non-free English learning applications and 31.6% of the participants have never tried to use smartphones for learning English. The conditions for promoting use of smartphones for language learning and the proper ways to design smartphone applications for English learning were discussed based on the research results.