This study examines the intrinsic motivations that drive the enjoyment of smartphone games and the influence of the characteristics of age, gender and playfulness on such motivations. Using Self-Determination Theory (SDT) from the discipline of psychology as a basis, a sample of 340 smartphone gamers was surveyed and the results were analyzed using a multiple linear regression approach. The consequent model was then tested in relation to two specific games to further validate the approach and provide a model that is relevant to individual games. This study thus provides a clearer idea of the nature of play as it develops in the era of the smartphone game as well as adding another layer to our understanding of intrinsic motivation due to the fact that smartphone games can be accessed as necessary for need satisfaction, to experience flow, to gain a sense of escapism and ultimately to allow a player to experience a sense of enjoyment. Given that smartphones now constitute an essential communication device, this represents a key change in that people can now access a mode of play almost at whim. Players now have access to an enjoyable experience that can provide satisfactions that other experiences in their daily life may not allow.