This paper explores the crossover between formal learning and learning in informal spaces supported by mobile technology, and proposes design principles for educators to carry out a science curriculum, namely Boundary Activity-based Science Curriculum (BAbSC). The conceptualization of the boundary object, and the principles of boundary activity as the key elements to fuse the merits of learning in informal spaces with formal learning, are discussed and elaborated. The key elements of BAbSC are further articulated to provide the framework for curriculum design and development from a holistic perspective. The proposed principles and framework will reinforce the theoretical underpinnings of mobile technology-enabled curriculum design and development, and can be used to guide teachers to implement curriculum in a more principle-based and structured manner.