In some cases, we may need to track multiple domains within a single Google Analytics 4 property. For this purpose we can configure multiple domains in the Data Stream settings.
Important note: You don’t need cross-domain tracking for tracking subdomains. GA4 tracks subdomains automatically.
1. Ensure that your domains are configured with a valid SSL certificate.
2. In the GA4 interface, go to Admin and select the property for which you want to set up cross-domain tracking.
3. Under the Property column, click on “Data Streams” and then select the data stream for the website that you want to track.
4. Click on the “Configure tag settings” tab below
5. Choose “Configure your domains” on the pop-up screen.
6. You can now list different domains based on conditions and tell GA4 to track them in the same property.
7. Click “Save” to save your settings.
Cross-domain tracking also defines which links on your site do not trigger Outbound Click events when using enhanced measurement.
Once you’ve completed these steps, GA4 will track user activity across the linked domains. If you have multiple data streams set up for a single property, you will need to repeat these steps for each data stream.
Note that cross-domain tracking may take up to 24 hours to fully implement, so you may not see data right away.
