Telefonica will offer pre-installed versions of Line on future Firefox OS devices it releases and plans to expand the deal to other countries. Telefonica has a customer base of about 320 million spread across 24 markets, so Line could potentially stand to boost its 300 million users significantly.

The deal will also involve joint marketing campaigns from both companies targeting Latin America, a market Telefonica hopes will latch on to the low cost Firefox OS handsets. Reports from last year say that Line was shifting its focus from the US to Latin America due to expected growth in the region. “We originally thought we’d move in on the US, but then Latin America grew faster than we thought, and the timing there was more critical,”  Line's US CEO Jeanie Han said.

While Line does stand to increase its visibility in the region, it will be doing so on the yet to be proven Firefox OS and against some already fairly established competition. China's WeChat has already tapped famous footballer Lionel Messi to be the face of its marketing campaign in the region. On top of that, messaging giant WhatsApp is also quite popular there, so Line will still have some work to do.