Google workers who want to return their offices in Kirkland and Seattle can do so starting April 20, the company has announced.

But the choice to go is voluntary until September, when a modified return to the office is planned. Until then, employees are free to continue working remotely.

Rendering shows what Google’s Kirkland Urban campus will look like upon completion. Rendering courtesy of Google.

Some buildings at Google’s Kirkland Urban and South Lake Union campuses will be among the first to open in the company after being the first to close in the U.S. when the pandemic emerged early last year.

The company employs more than 6,300 people in the Puget Sound region and continues to build out its Kirkland Urban campus, with plans for additional space in the city.

The offices will open at less than 20 percent capacity on April 20. Workers visiting the office will have the option to reserve a desk, Google said.

Come September, the company plans a broader return to offices while including options for some remote work.

The New York Times, citing an email from Sundar Pichai, CEO of Google parent Alphabet to staff, said Google planned to test a pilot workweek of at least three days a week in the office, with other days remote.

Google has been in Washington state since 2011.