How to Track Monthly iPhone Data Usage

Using iPhone eSIM to switch between carriers means adding more than one cellular plan, naming each plan, and choosing which plan handles voice, messages, and mobile data. On supported iPhone models, eSIM setup is done in Settings or by scanning a carrier QR code. Carrier switching works only if the iPhone is unlocked and both plans are active.

Steps

1. Open Settings > Cellular or Settings > Mobile Data, then tap Add eSIM or Add Cellular Plan. Follow the carrier method shown, such as QR code, carrier app, or manual entry.
2. Complete the add eSIM plan process for each carrier. Assign clear labels such as Primary, Travel, Work, or Carrier 2 to avoid selecting the wrong line later.
3. Go to Settings > Cellular and tap each line to confirm the line is turned on. A digital SIM iPhone can store multiple eSIMs, but only supported active lines can be used at the same time depending on model.
4. Under Default Voice Line and Cellular Data, select the carrier for calls and the carrier for mobile data. Turn Allow Cellular Data Switching on only if automatic switching is needed.
5. To switch carriers later, return to Settings > Cellular. Choose the line for voice, messages, or data, or turn one line off temporarily if only one carrier should stay active.

Common Issues and Fixes

• eSIM setup not appearing — Likely cause: unsupported iPhone model or outdated iOS. Fix: confirm eSIM support and update iOS in Settings.
• Carrier cannot be added — Likely cause: carrier does not support eSIM or the QR code is expired. Fix: request a new eSIM activation code or use the carrier app.
• No service after switching — Likely cause: line is inactive or not selected for data. Fix: check line status under Cellular and select the correct data line.
• Cannot use another carrier — Likely cause: carrier lock. Fix: verify the iPhone is unlocked under carrier lock status in About settings.
• Messages come from the wrong number — Likely cause: wrong default line for iMessage or FaceTime. Fix: review Message Send & Receive and FaceTime caller settings.

Quick Tips

• Some iPhone models support one physical SIM plus one eSIM active, while newer models may support two active eSIMs.
• Removing an eSIM deletes the plan from the device, but service cancellation usually must be handled with the carrier separately.
• International travel eSIMs often provide data only. Voice calls may still require the primary carrier line or Wi‑Fi calling.
• A restart after adding a new digital SIM iPhone plan can help the line register faster.

Can two carriers stay active on one iPhone?

Yes, supported iPhone models can keep two lines active at once. One line can handle voice while another line handles cellular data.

Does switching eSIM delete the old carrier plan?

No, switching between saved plans does not usually delete a plan. Deletion happens only when the eSIM is removed from Cellular settings.