Cephalopods have the largest invertebrate nervous systems and show complex behaviors in terms of learning and memory, motor skills, and camouflage. However, how neurons are activated and propagate information on a large scale during these complex behaviors is largely unknown. Genetically encoded fluorescent indicators have been revolutionary in reporting on neuronal activity during behavior in other animal models, but delivery of these indicators to cephalopods is challenging because of the protective layer of cells around the developing embryo, limited genomic integration of delivered genetic material, and the lack of viral vectors. Building on recent advances in the delivery of genetic material to squid, I will explore the delivery of genetically encoded fluorescent indicators that report on calcium dynamics. Successful delivery and functional imaging of calcium indicators in the squid will open avenues for delivering indicators for other signaling molecules such as second messengers, neurotransmitters, and neuropeptides, all of which are important for cephalopod physiology and behavior.