The move allows gamers to access nine titles that usually require a subscription, including Grid, Destiny 2: The Collection and Thumper.
After launching in November, players had to pay £119 for the Google Stadia Premiere Edition which came with a controller and Chromecast Ultra, as well as a £8.99 subscription fee after the first three months.
But now, the platform will be available to those with a Gmail account, via the Chrome web browser on a computer or smartphone, including Google's own Pixel range and some of the most recent Samsung Galaxy S handsets.
"We're facing some of the most challenging times in recent memory," said Phil Harrison, vice president and general manager for Google Stadia.
"Keeping social distance is vital, but staying home for long periods can be difficult and feel isolating.
"Video games can be a valuable way to socialise with friends and family when you're stuck at home, so we're giving gamers in 14 countries free access to Stadia for two months."
Google had always intended to launch a free tier of the Stadia platform restricted to buying individual titles only. Paid subscribers can also buy individual titles, but also have access to a rolling selection of free games.
The tech giant said those who have already subscribed to Stadia Pro will not be charged for the next two months.
Free access to Stadia is being rolled out over the next 48 hours to 14 countries, including the UK and Ireland.
Games available include Destiny 2: The Collection, Grid, Gylt, SteamWorld Dig 2, SteamWorld Quest: Hand Of Gilgamech, Serious Sam Collection, Spitlings, Stacks on Stacks (on Stacks), and Thumper.