Firefox for iOS adds a built-in ad blocker

Mozilla has built an Ad Blocker directly into Firefox for iOS, announced on the company blog on September 1. It uses Apple's WebKit Content Blocker technology and the EasyList filter list to block, in Mozilla's words, "many third-party ads and ad-related trackers before they load." This is a feature inside the app, not a separate App Store content blocker and not a paid add-on.

It is also off by default, so nothing changes until you switch it on.

What it actually blocks, and what it leaves alone

This is not a blanket ad wipe, and Mozilla says so on the page. By its own description the blocker does not touch ads the site you are visiting serves directly, ads in search results, or the sponsored shortcuts and sponsored content Firefox shows when you open a new tab. Those still appear. What it targets is the third-party ad and tracker layer that loads from elsewhere.

You turn it on at Settings, Browsing, Ad Blocker, and it runs alongside the Enhanced Tracking Protection Firefox already had, rather than replacing it.

Why Mozilla had to bake it in

On iOS, extensions "aren't available in the same way" they are on desktop and Android, and App Store ad blockers only work with Safari. So Mozilla embedded the blocker in the Firefox app itself instead of shipping a standalone extension. It is part of the free Firefox for iOS, with no separate tier or in-app purchase called out.

Firefox is not first here. Brave, Vivaldi and Opera already ship built-in ad blocking on iPhone, so this is Firefox catching up on iOS rather than opening a new category. Mozilla is also rolling the feature out globally in stages, so the toggle may not appear the instant you update the app.

The takeaway

If you browse on Firefox for iPhone, open Settings and turn it on, but treat it as one layer rather than the whole shield. The ads your sites and your searches serve, and the sponsored tiles on your own new-tab page, are still getting through by design. For the wider fight over who gets paid for those ads, see our coverage of OpenAI building ads into ChatGPT toward $1B in ad revenue, and for the iPhone that will run all of this, Apple's September 9 event under new CEO John Ternus.