Students are inseparable by their mobile phone. They do many things on the phone such as texting, uploading and downloading pictures and videos, reading the flash news, or just browsing. However, the rapid growth of mobile phone technology sometimes distracts them from their learn activities in the class. They don't put their focus much on the lesson because of the attention to their mobile phone. Thus makes teacher should be creative enough to find an alternative way to anticipate this phenomenon. Collaborative learning using collaborative tools tend to be applied due to its activities combine collaboration of students and the use of mobile phone application. This article attempts to study the use of WhatsApp in English language classroom to optimize the function of the mobile phone for students' learning process. Supported activities in four language skills are presented to give teacher choice of English teaching. It can be said that the integration of WhatsApp into their education will be easy, fun, and useful. Students get positive feelings and intentions regarding the possible use of WhatsApp in their formal learning.