Xbox said the limits were due to the rising cost of cloud gaming, and they would allow the firm to "continue to invest" in the service's "reliability and performance".
Cloud gaming allows players to stream and play games online from a remote server using a phone, tablet or controller, rather than downloading and running it on a PC or console at home.
Different tiers of subscription to Game Pass will have different limits.
Premium users will get 10 hours, while those on the basic Essential tier will get five hours a month before they have to pay for extra time.
Xbox claimed just 4% of the people who use Games Pass – its Netflix-style subscription plan for games – use its cloud gaming service.
"This is a pretty awful change, hopefully Xbox adds an extra zero on the end cause 15hrs is abysmal. 30 minutes a day, really?" posted one commenter on X, external.
Jez Corden of Windows Central told the BBC the announcement showed that "absolutely nothing is safe from the AI-driven component crisis," but he added it also highlighted "where Microsoft's priorities are".
Both cloud gaming and AI use the same infrastructure – data centres – to process information.
"For them to continue to offer unlimited access to Microsoft Copilot [AI] for free but restrict paid cloud gaming in this way shows some contradiction," he added.
Xbox said in a blog post, external that from November, users would also be able to use the company's cloud gaming feature without subscribing to Game Pass, but by buying "cloud playtime hours" through the Xbox store.
It has not revealed how much extra hours of cloud gaming would cost.
The news comes as Asha Sharma, Xbox's chief executive, told the BBC in an exclusive recent interview that the company and the industry as a whole needed to "start to innovate on affordability and efficiency," amid a "crisis" in computing prices.
"As an industry, we're in the middle of 'Rampocalypse'. We're in the middle of people coming back from Covid and the patterns changing," she said.
"Rampocalypse" refers to the fact that the cost of a previously cheap hardware component, random access memory (Ram), has shot up in price with the expansion of compute-hungry data centres. Some people also call it "Ramageddon".
Sharma added: "Within Xbox, we haven't been healthy. And so a lot of the reset that will take us throughout the year is really meant to help ensure that we are here for the next 25 years and we're continuing to serve our purpose and our mission."
