Mozilla is gradually rolling out a built‑in ad blocker for Firefox on iOS, a move that can help users protect their privacy more, except in some lucrative situations.

Introduced on Saturday via a support page, the optional blocker is experimental and being rolled out to all users. It blocks ads at the network level, affecting third‑party advertising networks, exchanges, ad‑related trackers, and many third‑party ads served by websites. The blocker also suppresses more intrusive formats such as pop‑ups and overlays.

The system uses a filter list based on Easy List and blocks ads before they load, but there are notable exceptions. Mozilla explains that the blocker will not block ads shown on search engine results pages, including Google, Bing, and Duck Duck Go, nor sponsored content on the Firefox Home or New Tab page. This preserves revenue from search deals, which in 2025 accounted for about 85% of Firefox’s income.

To enable ad‑blocking, open Firefox, tap the menu, select Site menu, tap Ad Blocker, and toggle it on in the Settings menu.