Instant messages may be automatically forwarded. A computing device may receive an electronic message and an indication of a sender-specified destination for the electronic message. The computing device may determine whether the destination is available to receive an electronic message using a first mode of communication. The computing device may determine whether a mobile telephone number is associated with the destination. The computing device may transmit a communication to the mobile telephone number based on the electronic message in response to determining that the destination is unavailable and that the mobile telephone number is associated with the destination.