In the same hall, after collecting your checked bags but before fully exiting the airport, you’ll find several booths and sales agents selling local SIM cards. They are legit so rest assured. If your phone does not come with a SIM card slot, they can help install an e-SIM for you. Either Viettel or Mobifone is fine.

If you are visiting HCM for a few days first, you can ask them to help you call a taxi back to the hotel as well. Tips are appreciated but not expected.

The country code for Vietnam is +84.