Samsung Galaxy Tab S3 starts receiving Android 8.0 Oreo in the US

Samsung kicked off the rollout of Android 8.0 Oreo for Galaxy Tab S3 about two weeks ago, but the update only started to show up in the US this week. If you're stationed in the US and own the Samsung Galaxy Tab S3, an update that weighs in at 1.23GB should be available for download in the coming days.
Also, the update is likely to include the May or June security patch. If you haven't yet been notified about the update, you can manually check for it or simply wait a few more days for the OTA to arrive.
source: AndroidPolice