This is according to a recent tweet by the official Android Twitter account in which it says that the first smartphone to ship with Android 10 is the OnePlus 7T. Given that the OnePlus 7T will only be released on the 18th of October, this means that the Pixel 4 smartphones will only be released after that, although it is entirely possible that pre-orders could be available on the 15h of October.
That being said, this shouldn’t be too surprising. Save for the Pixel 3a and 3a XL, Google’s previous Pixel phones have typically had a gap between its launch and its release, so for the Pixel 4 to be released after the launch date is pretty normal. In fact, we expect that there should be a gap of about a week between its launch and release, but either way do check back with us on the 15th of October if you’d like the details.
https://twitter.com/Android/status/1177295233954041857
In the meantime, Android 10 has already made its way onto various smartphones, including the Pixel handsets and phones from other manufacturers.