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IMSI selection

The Telnyx SIM profile is built with multi-IMSI technology. It has multiple IMSIs: the Telnyx IMSI along with 4 other IMSIs.

What are the benefits of multi-IMSI SIMs?

The Telnyx multi-IMSI SIM uses an intelligent applet to select the most appropriate IMSI for each location. For example, when a SIM enters a new country, it will automatically use the IMSI that provides the best coverage and rates in that country. Multi-IMSI technology offers the following benefits:

  • Customers benefit from multiple networks without managing multiple MNO providers.
  • Better coverage with better rates. Selecting from multiple IMSIs provides the flexibility to avail of the best coverage and rates both locally and globally.
  • Local IMSIs ensure devices natively connect to local networks instead of roaming, meaning lower latency connectivity and compliance with roaming regulations.
  • An intelligent applet built into the SIM automatically selects the most appropriate IMSI in each location with no change required to the device.

What IMSIs are available on the Telnyx SIM profile?

  1. Telnyx
  2. Sparkle
  3. BICs
  4. T-Mobile
  5. US Cellular

Should I use automatic or manual IMSI selection?

By default, IMSI selection is automatic. An intelligent applet on the SIM selects the most appropriate IMSI to use in each location. This is the recommended setting.

However, it is possible to manually select a specific IMSI. This must be done on the device, and requires the mode to be changed from “Automatic” to “Manual”.

NOTE: If the mode is changed to “Manual” to enable manual IMSI selection, the SIM will not default to intelligent IMSI selection in the event that the device moves location, unless the mode is changed back to “Automatic”. For this reason, it is recommended that the mode be immediately switched back to “Automatic” after an IMSI has been manually selected. This will ensure devices maintain seamless connectivity no matter where they are deployed.

How can I manually select a specific IMSI?

For Android:

On Android devices, there is an app called “Telnyx” or "Telnyx UICC" or "SIM Toolkit" that will appear when the Telnyx SIM is in use. Open the app, then select:

Telnyx > Selection mode > “Manual” > IMSI Selection Menu > select the desired IMSI > Selection mode > “Automatic”

For Apple:

On Apple devices:

Settings > Mobile Service > select the eSIM > SIM Applications > Telnyx > Selection mode > “Manual” > IMSI Selection Menu > select the desired IMSI > Selection mode > “Automatic”


To ensure seamless coverage, switch the mode back to “Automatic” after an IMSI has been manually selected to re-enable automatic IMSI selection via the intelligent applet.

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