Google Fi now offers an unlimited plan

Pay a flat fee for unlimited data, calls and texts.

Google's mobile virtual network operator service Fi works by piggybacking on wireless networks to provide cellphone coverage. Last year it opened up to work with iPhones, and earlier this year SIM cards for Fi went on sale at Best Buy. Now, the service is expanding further with a new unlimited plan.

The Fi Unlimited plan offers unlimited calls, texts and data for multiple members of your family, including some international calls. The plan covers free calls from the US to 50 countries, as well as free data and SMS messages when you are traveling in 200 destinations. The plan also comes with a Google One membership, giving you 100GB of cloud storage onto which you can automatically back up your Android phone.

The monthly cost of the Unlimited plan is $45 per line for 4 to 6 lines, $50 per line for 3 lines, $60 per line for 2 lines and $70 for a single line. That's pricey, but the upside is that there's no contract or activation fees.

If you're keen for both a new phone and a new plan, you can get 50 percent off a Pixel 3 or Pixel 3XL when you sign up for Google Fi by September 18th.

To see if Google Fi is available on your device, you can check the compatibility page.