# Switch SIM Card

Many of our OutdoorRouter models, including the EZR23(T), EZR33(L/T), and EZR34(T), have dual SIM card slots. By default, the router uses SIM card #1 as the primary card. The two SIM card slots are connected to the same 4G/5G modem. Only one SIM can be active at a time.

## Active SIM Card

### Check SIM Status

To check which SIM card is currently active, go to the "***Device***" section on the right side of the homepage or navigate to "***Network > Mobile***." The interface will indicate whether SIM 1 or SIM 2 is in use.

### Change Active SIM

To change the active SIM card:

1. Go to "***Network > Mobile***" and select "***Edit***."
2. Under the "***General Setup***" tab, choose either "***Primary SIM 1***" or "***Secondary SIM 2***" from the "Active SIM Card" drop-down menu.
3. Click "***Save & Apply***" at the bottom of the page to confirm the change.

The router will switch to using the newly selected SIM card. No need to reboot the router. It takes a few minutes to redial for mobile connection through the new SIM card.

<div align="left"><figure><img src="/files/sQx7RTFJneSC2axxJaUV" alt="" width="375"><figcaption><p>Active SIM and Auto Switch SIM Cards</p></figcaption></figure></div>

***

## Auto Switch SIM

If you are in an area with uneven cell signal coverage and need reliable internet, use the secondary SIM slot to insert a SIM card from another carrier. Go to "***Network > Mobile: Edit***" and enable the "***Auto Switch SIM Card***" function.

When enabled, the [***Mobile-Watchdog***](/mobile/mobile-watchdog.md) will continuously check the active SIM's internet status. If the watchdog detects the active SIM is offline, the router will automatically switch to the secondary SIM for failover connectivity. This ensures the router maintains internet access even if a carrier's intermittent signal.

The auto-switch function provides seamless cellular connectivity failover using dual SIMs from different carriers.


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://how.router.works/mobile/switch-sim-card.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.