The internet has been widely used to promote collaborative learning among students. However, students do not always have access to the system, leading to doubt in the interaction among the students, and reducing the effectiveness of collaborative learning, since the web-based collaborative learning environment relies entirely on the availability of computers and the internet. A web-based collaborative learning scheme based on activity awareness carried out through mobile phones is proposed herein. The proposed mechanism automatically sends SMS messages on a GSM network, based on student identity and learning activity, making the student aware of the collaborative learning context, and further improving the student's learning. A web-based collaborative learning activity was implemented in a Taiwan undergraduate class to examine the proposed scheme. Experiments demonstrated that awareness of the collaborative learning context through mobile phones significantly increased student participation in learning activity and improving student learning performance. (Contains 4 figures and 5 tables.)