I have used AirSIM for Taipei, Indonesia and Malaysia. It worked well.
AirSIM provide a separate SIM card. It can be used as the local SIM card for many countries. I can buy a local data plan at a price that is only slightly higher than the local data plan rate.
Here is an example. If I go into country X, I can buy a local SIM card for that country and purchase a local data plan. I have to pay for the SIM card at the airport and also register as the owner of that card. I need to queue up at the booth to make the purchase.
With AirSIM, I avoid the need to buy a local SIM card. I can use the SIM card that is provided by AirSIM and buy a data plan for that country.
Better still, I can buy the data plan in advance and set the effective date.
Early this week, I bought the data plan for Malaysia for Thurs and for Indonesia for Sun and Mon. I bought them in advance and set the starting date.
I travelled to Johore today and the data plan came on when I arrived in Johore. I had tried it for an earlier trip to Taipei and Jakarta, and it worked as expected.
The AirSIM app is easy to use. It is much better designed that the Starhub app. I had a lot of trouble with the Starhub app which was quite confusing to me. I did not have any trouble with the AirSIM app.
The AirSIM service is much better than Starhub from another angle. It gives unlimited data usage and does not charge extra when the data package is fully used. However, if I used more than 500 MB for a day, it automatically reduces the speed, but do not levy an exorbitant charge for the excess data.
In the case of Starhub, I had to pay for the excess data at a "robbery rate", which could be a few thousand times of the normal data rate. I could not find out what this "robbery rate" is.
For my travel outside of Singapore, I will be using AirSIM from now.
If you are interested to use AirSIM, you can register an account at airsim.com.sg. They will send you a SIM card and give instruction on how to use it.www.airsim.com.sg