Truphone is a mobile VoIP/internet telephony operator. It provides Symbian software and a network infrastructure that allows people to make telephone calls and send SMS text messages over the internet from WiFi-enabled? Nokia Series 60 smartphones. A version for the Apple iPhone was also released in July 2008. Calls and SMS texts to other online Truphone users are free, and calls or texts to other numbers are chargeable.

Truphone uses the Session Initiation Protocol (SIP) open standard, which competes with other VoIP standards such as UMA and proprietary protocols such as Skype.