No, you don't need a phone line for Viasat satellite internet service, even if you sign up for Viasat Voice phone service. That's because the Voice service uses voice over internet protocol (VoIP) technology instead of a phone line. That said, Viasat now offers a Flex plan that combines satellite internet with DSL internet—and DSL internet travels over phone lines. So to get Viasat Flex (and potentially better internet speeds), you'll need a phone line.