Dozens of gamers at the show lined up on Tuesday to register their devices for the opening competition, which runs until 9 p.m. on Wednesday night. Players gaining the most points will unlock hidden prizes at I/O and also free drinks at a special Ingress meetup being held later during the conference, Google said.
The game was developed by Google's Niantic Labs, which is also the workhorse behind Google's Field Trip location discovery app for Android and iOS devices.
Field Trip is designed to alert users to interesting landmarks, locations and places of historical significance as they go about their day.
There is some overlap between Ingress and Field Trip. Some of recommendations provided by Field Trip may also appear reconfigured as portals in Ingress, but getting more personal geolocation data is not what Ingress is about, Google argued at I/O.
"The game is about just getting out there and enjoying your local community," one rep said.
Google I/O officially begins Wednesday morning.