For Universal, Expedition, & eSIM World ONLY: Just dial 099 "Send" from your OneSimCard phone and in few minutes the balance will be displayed on the screen of your phone. Customers with iPhones can use OneSimCard Assist app to check balances and many other things.

You can always check your current balance by logging onto your OneSimCard account at www.onesimcard.com.

To make a call:

• Dial 00-CountryCode-AreaCode-Number and press the TALK/SEND button.
  Example: To call OneSimCard Support in the USA you would dial 00 1 617 3138888 and press TALK/SEND. 

With Europe & More, Univesal and eSIM World that do not use the callback to make a call, you will just get connected.
 
With OneSimCard Plus SIM or Expedition (formerly Data & Roam) SIMs:

After pressing the TALK/SEND button you will see a variable message on the screen (for example 'Wait for call') which you can ignore and your phone will ring back in a few seconds. Answer this ring as you normally would answer any incoming call. Your call will then be connected.

If you are unsure about how to properly dial an international number, follow this link for detailed country by country dialing instructions.

For DataMax, and DataMax eSIM cards, you can place calls using our low cost OneSIM VoIP service. OneSim VoIP costs much less than traditional voice roaming.