The research literature reports on designs of ubiquitous and seamless learning environments enabled by the integration of mobile technology into learning. However, the lack of good pedagogical designs that provide for sustainability and the inadequate investigation of learning outcomes remain major gaps in the current studies on mobile learning. This paper seeks to contribute to addressing these issues by reporting on a study concerning the principles of integrating mobile learning into a standards-based science curriculum. It also explores how mobile learning activities have impacted students' academic and activity performances in and out of the classroom over a whole academic year. Mixed methods were used to examine students' performances, and a yearly comparison was made for assessing students' progression in their conceptual understanding in science. Data analysis on students' test results, mobile learning artifacts, and their activity performances in the classroom suggested that they had improved in their conceptual understanding and self-reflection on these conceptual changes. Students were engaged in mobile learning activities both in the classroom and out of the classroom through sustained exposure to and experience of the mobilized science curriculum.