Summary
Navigate to plans.sidephone.com, select a desired plan type, and follow the activation steps. Once your plan has been initialized, insert the provided SIM card into Sidephone and follow any remaining activation steps. Sidephone works best with T-Mobile and T-Mobile MVNOs in the US.
Steps
Activate your mobile plan
Navigate to plans.sidephone.com
Enter your email to create an account
Choose your plan type
Choose whether to port-in an existing number or create a new one to use with Sidephone
If porting-in an existing number, unenroll from iMessage/RCS before porting-in
Provide a method of payment
Complete activation
Insert and activate your SIM
Complete initial setup prior to installing the SIM card
Power off Sidephone
Insert your activated SIM card into the SIM tray
Power Sidephone back on
Wait for the device to register on the network (signal bars should appear)
This may take up to 10 minutes
Follow guidance from incoming text messages (if applicable)
Confirm connectivity
Open Settings → Network & Internet → Mobile network
Confirm your carrier name is visible and mobile data is enabled
Place a test call or send a text to verify service
If you prefer Wi-Fi only (optional)
Skip inserting a SIM if you do not want cellular service
Connect to Wi-Fi in Settings → Network & Internet → Wi-Fi
Use internet-based apps (e.g. messaging via compatible services) over Wi-Fi
Considerations
Open and unlocked: Sidephone is an open unlocked phone. It is not required that you use Sidephone's mobile service.
Best carrier compatibility: Sidephone works best with T-Mobile and T-Mobile MVNOs in the US. Verizon does not support Sidephone at this time.
Why Sidephone mobile: We designed Sidephone's mobile plans to work best with Sidephone, and to ensure that everyone has at least one mobile option available to use. We will continue to invest in the Sidephone plans in order to provide members with exclusive benefits over time.
Roaming: Sidephone plans do not have roaming options available at this time. We are evaluating partnerships with pSIM to eSIM partners that may unlock apps like Saily for Sidephone.
No signal after inserting SIM: Toggle Airplane Mode on/off, then wait 1–2 minutes.
SIM inserted before Setup Wizard: This is acceptable; you can still complete setup normally.
Using a non–T-Mobile carrier in the US: May work, but compatibility and performance may be impacted.
Data works but calls/text do not: Confirm your plan supports voice/SMS (not data-only). Ensure your have un-enrolled your phone number from RCS and iMessage.
When to Contact Support
Create a support ticket if Sidephone shows no signal after a valid, activated SIM is inserted and mobile data is enabled, or if calls/texts consistently fail on a supported T-Mobile plan.
What to Collect for Support
Carrier name (e.g., T-Mobile or MVNO)
Whether the SIM is confirmed activated in another device
Whether signal bars appear on Sidephone
Whether mobile data is enabled in Settings
Whether calls and/or texts work (specify which fail)
Any on-screen error messages