IDFA & GAID Opt Out Guide

What An Advertising Identifier Actually Is

Every modern smartphone and tablet carries a resettable advertising identifier. On Apple devices it is called the IDFA, the Identifier for Advertisers. On Android it is the GAID, the Google Advertising ID. It is a random string of characters assigned to the device — not to you by name — and advertising platforms use it to count how many times an advert has been shown, to avoid showing you the same thing twenty times in a row, and to measure whether a campaign led to a visit or a purchase.

It is deliberately designed to be resettable and switchable. You are in control of it, and you can change or disable it at any time without affecting how your phone works. Turning it off does not reduce the number of adverts you see. It changes how relevant they are, because advertisers lose the signal that lets them tailor and cap them.

Why this page exists

We run mobile geo-location and geo-fencing campaigns for clients, which rely on advertising identifiers to deliver adverts to devices that have been in a defined physical area. Those identifiers are personal data under UK and EU law, so anyone whose device may be included is entitled to a clear, honest explanation of how to opt out. That is what follows.

Turning it off on an iPhone or iPad

Since iOS 14.5, apps must ask your permission before they can access the IDFA at all, through the App Tracking Transparency prompt. To review or change your choice:

1. Open Settings.
2. Tap Privacy & Security.
3. Tap Tracking.
4. Switch Allow Apps to Request to Track off to refuse every app at once, or turn individual apps off in the list below it.

When this is off, your device returns a string of zeros instead of an identifier, and apps are not permitted to ask again. You can also limit Apple's own personalised adverts under Settings, then Privacy & Security, then Apple Advertising.

Turning it off on Android

The exact wording varies a little between manufacturers and Android versions, but the path is broadly the same:

1. Open Settings.
2. Tap Google, then All services if your device shows that tab.
3. Tap Ads.
4. Tap Delete advertising ID to remove it entirely, or Reset advertising ID to generate a fresh one.

Deleting the identifier means apps requesting it receive a string of zeros. Resetting it instead keeps personalisation working but disconnects it from everything previously recorded against the old identifier, which is a good habit every few months even if you are comfortable with personalised advertising.

Resetting rather than deleting

Resetting is the middle path. Your device gets a brand-new identifier, all the history built up against the old one is orphaned, and advertisers effectively meet you as a new device. If you want relevant adverts but do not want a long-running profile, reset periodically.

Browser advertising on the same device

The identifier only applies to apps. Adverts you see while browsing the web on the same phone are driven by cookies and similar technologies, which are handled separately. Use your browser's own privacy settings, and adjust your consent choices for any individual website through its cookie controls.

Industry-wide opt-out tools

Beyond the device settings, the advertising industry provides central opt-out pages. The Your Online Choices site, run by the European Interactive Digital Advertising Alliance, lets you opt out of behavioural advertising from participating companies in one place. The Network Advertising Initiative and Digital Advertising Alliance run equivalent tools. These are cookie-based, so you will need to repeat them on each browser, and they will be cleared if you clear your cookies.

What happens to data already collected

Once you delete or reset the identifier, no further activity can be attributed to the old one. If you want data already held about a device to be erased, you can exercise your right to erasure with us directly, and we will pass the request on to the platforms acting on our instructions.

Contact us about your data

If you want to ask what is held, request a copy or ask for deletion, get in touch and we will handle it within one calendar month. There is no charge and you do not need to give a reason for a marketing objection — an objection to direct marketing is absolute and we will action it immediately.