We get this question all the time at Prepaid Plans “What sim card should I be using if I am planning to travel overseas for a holiday? Simple answer is if you are planning to spend more than a week at one destination or if you are planning to make lots of local calls, then getting a local prepaid sim card is usually the best value for you.
If this isn’t the case and you want to find out what which Australian carriers have coverage (roaming) in the country you wish to visit, then you are best to visit this site: http://gsmworld.com/roaming/gsminfo/index.shtml
From this page you can select the destination you are going to, it will then show you the local operators and what roaming arrangements they have in place with local Australian carriers. Fro example, if I was traveling to Greece, I would find Greece in the list and it would show me that the local carriers are Cosmote, Vodafone and Wind. Each of these carriers has roaming relationships in place. Cosmote for instance has a relationship with Optus, Telstra and Vodafone.
You would need to check out what roaming charges your mobile plan has with the destinations you are traveling to. Roaming is generally only available by Telstra, Vodafone and Optus prepaid mobile plans.
