A communication system according to an embodiment includes a server system and one or more communication apparatuses. The server system includes a first hardware processor. The first hardware processor determines frequency information indicating processing frequency of predetermined processing executed by the communication apparatuses. The frequency information is determined on the basis of determination information affecting the predetermined processing. The first hardware processor transmits processing frequency of the predetermined processing to the communication apparatuses. The processing frequency is determined on the basis of the frequency information. The communication apparatuses each include a second hardware processor. The second hardware processor receives the processing frequency of the processing from the server system. The second hardware processor executes the predetermined processing on the basis of the received processing frequency.