Google just plugged itself straight into Japan.

This week, a new undersea fiber-optic cable funded by Google and a consortium of Asian telecommunications companies went online. Dubbed Faster, the cable stretches about 5,600 miles from Oregon to two landing points in Japan. It's the fastest, highest capacity trans-Pacific undersea cable ever built. It can theoretically deliver as much as 60 terabits per second of bandwidth—more than half the total bandwidth available between the U.S West Coast and Asia at the end of 2015, according to telecommunications consulting firm Telegeography.

Google is reserving 10 terabits of that capacity to speed up communications between its own computer data centers. The timing is fortuitous: Google announced in March that it will offer its cloud computing services from Tokyo later this year. It will also help make the Internet more resilient in earthquake prone parts of Asia. "The cable utilizes Japanese landing facilities strategically located outside of tsunami zones to help prevent network outages when the region is facing the greatest need," reads a Google blog post trumpeting the cable's grand opening.

Google and its partners—including China Mobile International, China Telecom Global, Global Transit, KDDI, and Singtel—first announced the project in 2014, and Japanese technology giant NEC actually laid the cable down.

This is Google's fourth undersea cable, and according to the company's blog post, it plans to invest in more in the future. The news follows last month's announcement that Facebook and Microsoft are teaming up to build a 160 terabit trans-Atlantic undersea cable stretching from Virginia to Spain. Google's role in the creation of Faster is less ambitious. It's just one of six companies participating, and most of Faster's capacity is going to traditional telecommunications companies. But it's the latest indication of how just how much bandwidth these tech giants are devouring. "We are seeing a very clear trend towards private networks becoming the major users of international submarine cable capacity," says Jonathan Hjembo, a senior analyst at Telegeography.

Traditionally, these cables carried public Internet traffic. Now, companies like Facebook and Google are using them to ferry data between their own data centers, bypassing the Internet to speed up content delivery. According to Hjembo, private networks now use 60 percent of the capacity of trans-Atlantic cables.

Meanwhile, Facebook and Google are also buying up "dark fiber"—unused fiber optic capacity throughout the US—to connect their various data centers on land. In short, a handful of large tech companies are slowly eclipsing the bandwidth capacity of traditional telcos, underscoring just how big these tech giants have really become. But Hjembo points out that there's no shortage of capacity. The real point here is that companies like Google want to own their own cables. Or, as Facebook’s vice president of network engineering Najam Ahmad told us earlier this year, these projects allow the companies to control their own destinies.