Project Loon, the ambitious initiative to bring balloon-delivered internet access to remote areas and developing countries, is partnering with three of Indonesia's biggest telecom companies for a country-wide test period starting next year, Alphabet announced today. Executives from the three companies — Telkomsel, XL Axiata, and Indosat — revealed the plan alongside Loon project leader Mike Cassidy and Alphabet president / original Google co-founder Sergey Brin at a press event in Mountain View, California. Indonesia marks the fourth country behind Brazil, New Zealand, and Australia in which Loon will fly its balloons more than 12 miles in the sky to beam down internet access to any LTE-capable smartphone.

Loon began in 2011 as part of Google X, Alphabet's secretive "moonshots" lab, though Brin says the division is provisionally being renamed simply X. Though Google restructured itself as Alphabet in August, the company kept Loon under the moonshot lab's banner. Loon's first testing period in New Zealand involved 30 balloons in 2013, followed by Australia and Brazil. Those tests helped inform Loon's current approach of partnering with telecoms, which own defined parts of the spectrum, instead of trying to negotiate unused parts of the spectrum to use for free. In Indonesia, Cassidy says they'll plan to send up hundreds of balloons.

A Project Loon graphic describing how the balloons drift in the stratosphere above airplanes and natural weather phenomena.

For Indonesia, expanding internet access is important because only one out of every three residents can connect to the web today. Even when connected, the data speeds are incredibly slow by modern standards. With Loon, Google is able to take a signal produced from one of Indonesia's telecom companies and redistribute it through the skies.

From there, the signal can bounce among various balloons and blanket otherwise dead sections of the country with what cellphone owners will see as a standard Wi-Fi network. The download speeds will be up to 10Mbps, which is only 1Mbps below the average speed in the US as of August 2015. An air-based satellite network is especially useful in a country like Indonesia, the Loon team says, as the country stretches more than 740,000 miles across 17,000 islands.

A network of air balloons beaming Wi-Fi across 17,000 islands

For Aphabet, the Loon project is part of the company's efforts to bring online the more than 4 billion people around the globe without internet access. More internet users translates to more users of Alphabet products and services, especially Google search and its Android operating system, which is the world's most dominant mobile software and especially strong in developing countries that prefer low-cost handsets. The company has brokered deals in the past to bring Loon testing to Chile, Argentina, and Sri Lanka.

Alphabet isn't the only company vying to bring the entire planet online. Facebook has an initiative of its own, Internet.org, that it plans to pair with a fleet of autonomous and solar-powered internet planes its developed thanks to its acquisition of drone maker Ascenta. The high-flying Facebook plane, called Aquila, has a wingspan of a Boeing 747 and is designed to stay in the air for up to 90 days to deliver internet access to rural areas. Though their approaches differ, Facebook and Google are going head-to-head in the skies to become the go-to company for telecoms to partner with for high-speed internet access.