The ZTE Open handset will cost US$90, including a prepay balance of US$39, and comes with a 4GB microSD card although Telefonica is providing an option of zero interest financing.
The operator says it will be launching in other countries including Colombia and Venezuela in the coming weeks with Latin America having remained the focus of Mozilla since the first announcement in January.
The operator also revealed that it would be launching a range of devices for different prices targeting the middle-income market and the low end segment depending on how the phone is received by the market.
Telefonca Espana in a statement also says the open device will give consumers an option and flexibility of using different platforms.
Luis Miguel Gilpérez, chief executive officer (CEO) of Telefónica España, said: “We believe that smartphones need to be more open and that the web is the platform for making this possible.
“Consumers should not be locked to any one system but have the choice to consume the content they want and the flexibility to be able to take it with them when they change devices.
“This first open web device marks a significant milestone in making this possible. This is just the beginning as we plan to bring a wide range of Firefox OS devices to our customers.”
The device has a 3.5-inch touchscreen, 3.2MP camera, 256 RAM and 512MB ROM.
The Firefox OS can support HTML 5 applications.
Other than from Telefonica, other operators considering running the device on their network include Etisalat.