Phone It is advisable to buy an Indonesian SIM as they are inexpensive to purchase and you can easily send SMS to the Netherlands. You can top up your credit (pulsa) anywhere in Indonesia. XL or Telkomsel are good providers.
TIP!!! Don’t pay attention to the price differences of SIM cards from the same provider. Indonesians are willing to pay more for the phone number. The price difference is in the number, not in the quality of the provider.
Post. Packages to Europe take one to two weeks. It is best to mail cards and letters at the post office and ask them to stamp the postage directly.
Internet. It somewhat depends on the island you are on, but internet is becoming increasingly common in Indonesia. Many hotels offer it (also wireless/hotspot). However, do not expect fast connections. On the smaller islands, internet is still not standard.
Tip!!! Using the internet on your phone with an Indonesian SIM is very affordable and easy. Often they cut the SIM card to the right size for your phone!
Voltage. 220 volts is common in Indonesia, especially in hotels and restaurants. A plug, as known in most western countries, is also suitable for normal use. For exceptions, a universal adapter (available at ANWB or duty free at Schiphol) is always handy and not too bulky.