Sony announced the change in an update to its July 27th PlayStation Plus blog post, where the company notes that this is the first time it's raised Plus prices since launching the service in 2010.
"The new pricing reflects the current market conditions while enabling us to continue providing exceptional value to our members," Sony writes. "As a member, you will continue to enjoy the benefits and features that enable shared experiences, such as online multiplayer, free games and exclusive discounts. You will also continue to get exclusive benefits such as online game save storage and discounts across the PlayStation digital services."
Any current subscribers who want to ditch Plus before the new prices take effect, turn off auto-renewal in your account settings before September 22nd.