mIRC is a full featured Internet Relay Chat client for Windows that can be used to communicate, share, play or work with others on IRC networks around the world, either in multi-user group conferences or in one-to-one private discussions.mIRC is a full featured Internet Relay Chat client for Windows that can be used to communicate, share, play or work with others on IRC networks around the world, either in multi-user group conferences or in one-to-one private discussions.