You require a active mobile account pre or post paid.
Data/Calls/Messages will be charge at the pay as you go rate applicable to the interaction zone you're in outside any AU plan you're on.. I.e. current Data/Calls/Message plan/package is for Australia use only.
Note..This is an open and public support forum please refrain from posting private/personal information. 😉 __________________________________________________________________________ I’m a Yes Crowd Champion (not an Optus employee). I share my knowledge on Yes Crowd on a voluntary basis. If I answered your question, please mark it as a Accepted Solution. If I helped you out, hit that Kudos button