How to migrate all old data from Google Analytics 3 to GA4?

Question

I have some Wordpress websites that i use the old Google Analytics 3.

I move it now to the new GA4, but i can't see on new ga4 the old data from GA3.

I have add on old ga3 on Tracking ID of ga4 at "Tracking Code>Connect a tag" and have pass more of 48 hours and i can't the old data from ga3.

I believe i have done something wrong, can you help me and tell me me step-by-step what i have to do?

Answer 1

Two systems are very different.

The best way to switch is dual-tagging approach. It lets you build a historical record in Google Analytics 4 while continuing to depend on Universal Analytics until you're ready to switch over, so follow the step describe in the official documentation: https://support.google.com/analytics/answer/10759417?hl=en