We are here to help you get answers to your questions about OneSimCard phones and services.
How can I contact customer support?
There are a number of ways you can contact customer support.Can I be notified of missed calls when my phone is off or outside of a coverage area?
Yes, for Universal, Expedition, and eSIM World Sim Cards, you will receive SMS or email notifications when you miss a call due to your phone being off or out of coverage. SMS notifications are sent when the phone is unavailable for a period up to 4 hours. Email notifications are sent, regardless of the time period, to the email address you have entered into your online voicemail profile. Notifications will be sent when you make/receive a call or enter a new roaming country. NOTE: if the caller leaves a voicemail message then you will not receive this extra missed call notification.Is there a mobile app that will let me recharge my account and other services?
Yes! Our myOneSim app for the iPhone devices will let you easily access many account services, such as recharging your account, checking voicemail, ordering discount voice and text plans, and much more. MyOneSim is available for download from the App store. Find more information in the Help section of your online account.
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DataMax SIM cards can't be managed by myOneSim app at this time
Can I disable per MB/Pay-As-You-Go data usage for DataMax SIM cards
Yes you can. On your online account, in the "My SIM cards" menu, you will see a section labeled "Select SIM Card." In that section there is a line labeled "Use w/o Plan." If you do not want to use data on a per MB/Pay-As-You-Go basis, and only consume data with a data plan, set this to "Off."Do I need to have Data Roaming turned on for eSIM to work?
Yes. Data Roaming should be enabled on your phone for eSIM for data to work. Calls and texts on eSIM World should work with or without it.
What Is the Difference Between "Direct Dial" and "Callback Dial" calling?
Direct Dial calling allows the caller to enter the international call prefix, country calling code and telephone number and then be directly connected to the person they are calling. This is how you dial when using your regular mobile service. Direct Dial Calling is standard on the OneSimCard Europe & More, OneSimCard Universal and eSIM.
Callback calling also allows the caller to enter the international call prefix, country calling code and telephone number. After the called number is entered, the user immediately receives an incoming call connecting the user to person called. Callback is very simple to use and allows for low cost calling on the OneSimCard Plus and OneSimCard Expedition (formerly Data & Roam). Callback does not increase the connection time. It is the same as with Direct Dial.
What are the advantages of using OneSim VoIP?
The main advantages are significant cost savings and the ability to call from countries where there is no voice roaming coverage available, or for DataMax or DataMax eSIMs
OneSim VoiP can be used from any Android or Apple ( iOS) device to make international LD calls even when you are not traveling. OneSim VoIP does not require having OneSimCard SIM being installed in the phone. OneSim VoIP can be used with Wi-Fi or 3G/4G - no difference. You just need to have OneSimCard account with the SIM VoIP capable PEN. Calling using OneSim VoIP will cost most of the time less than any other way of calling.
OneSim VoIP is available with the following SIM cards: Plus, Expedition (formerly Data & Roam),  Europe & More, DataMax, and DataMax eSIM.When I dial following your instructions it does not work. What's wrong?
This answer applies to SIM cards purchased before January 1, 2017.
Some phones, such as Samsung, some Motorola, Android and Apple iPhones, require special dialing instructions or simple OneSimCard settings menu changes in order to make calls.
It is possible to make almost any phone entirely compatible, so you can call directly without using the OneSimCard menu or *146* by following these simple programming instructions below.
How to activate compatibility mode:
 1. Locate OneSimCard Menu.
 On iPhones it is called SIM Applications menu and is located under Settings- Phone menu
     On Androids it is called SIM Toolkit app or OneSimCard app and it looks like one of the apps.
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Bear in mind that if you have powered your telephone down, and have removed and reinstalled the battery, you will need to follow the programming steps outlined above, again.
If for any reason after entering compatibility code, you still do not get a ringback or you get the ringback the first time you make a call, but second time it would not work, please enter code 802 into the Service Code window instead of 1101 as provided above.
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iPhone users can download OneSimCard Assist App from iTunes that will takes care of the iphones compatibility issues, except for removing the ringback.
For example, calling to USA:Â Dial *146*0016175551212# and press the TALK (or SEND) button
The sequence *146* and # at the end can be used from any phone. However, most phones do not require it.
We strongly recommend you to watch very short video tutorials that will help you to understand how to make calls, SMS and data on your OneSimCard Phone.
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I just activated my SIM card and can't make a successful test call. What's wrong?
If you just activated your SIM card and can not make a test call by following the instructions in the user manual, you will likely just need to power off the phone and power it back on again. The phone should automatically re-register with one of our partner networks. Remember, if you answer the test call when it rings you will be charged for the call.I have more than one Personal Extra Number (PEN). Can I use different PENs for OneSim VoIP?
If you have more than one OneSim VoIP enabled PEN you can switch between these PENs for the purpose of the OneSim VoIP account. This option is available in the My SIM Cards menu in your online account.© 2006-2025 Belmont Telecom Inc., DBA OneSimCard.com. All rights reserved