An information processing system includes a first device that outputs a first access request conforming to a first communication protocol, a first relay device that converts the first access request into a second access request conforming to the second communication protocol and outputs the second access request, a second relay device that converts the second access request into a third access request conforming to the first communication protocol and outputs the third access request, and a second device outputs data, based on the third access request, wherein the first relay device receives the data via the second relay device and holds the data, after which the first relay device receives a fourth access request from the first device and outputs the data held therein to the first device.