Anopheles gambiae larvae have frequently been observed to dive, but the ecology of this behavior has not been extensively examined. We manipulated food level, water depth, and temperature for individually-reared larvae and observed diving activity. Larvae dived more often under low food, which suggests that they dive to forage. There was only weak evidence for effects of water depth or temperature on diving. Experimental results are discussed in the context of energy budgets. Understanding larval ecology of this species is important for predicting how it will respond to environmental change. Further study is needed to assess the role that larval diving plays in both feeding ecology and thermal regulation of this and other medically important species.