Google Play developers are being asked to change how they implement adverts to ensure "high quality experiences" for users and players.

New advertising guidelines being ushered in by Google on September 30, 2022, will prevent adverts from being shown in "unexpected ways" and will effectively ban certain types of adverting including full screen interstitial adverts that hit users when they take certain actions.

"Ads that appear during game play at the beginning of a level or during the beginning of a content segment are not allowed," said Google on its support website. "Full screen video interstitial ads that appear before an app’s loading screen (splash screen) are not allowed.

"Full screen interstitial ads of all formats that are not closeable after 15 seconds are not allowed. Opt-in full screen interstitials or full screen interstitials that do not interrupt users in their actions (for example, after the score screen in a game app) may persist more than 15 seconds."

Google notes its new policy doesn't apply to rewarded adverts that are explicitly opted-in by users, such as adverts that can be watched in exchange for an in-game reward. The new guidelines also won't apply to monetization and advertising that "does not interfere with normal app use or gameplay" -- so, for example, video content with integrated ads or non-full screen banner ads.

Running though some examples of common violations, Google said unexpected ads that appear during gameplay or at the beginning of a content segment will be prohibited as users don't expect to be shown a piece of marketing at those points.

Google reiterated that all new and existing apps must comply with its updated advertising guidelines, and said that developers will be given a grace period of 30 days to implement any necessary changes.

For more information on the new rules, including more examples of prohibited advertising, visit the Google Policy Center.