@Nickroamer 

To use the data roaming function on a 4G LTE Router, you typically need to have an active data plan with your mobile service provider that includes international roaming services. It's important to note that data roaming may incur additional charges, and the rates for data usage vary depending on the mobile network and service provider.

By enabling data roaming on your SIM card and 4G LTE Router, you could stay connected to the internet and access online services while traveling abroad without the need for a local SIM card.

Please follow the steps below to enable Data Roaming on TP-Link 4G LTE Router:

1. Log into the Web UI via http://tplinkmodem.net

2. Go to Advanced > Network > Internet, and enable "Data Roaming".

If the data roaming feature doesn't work, you can perform the following troubleshooting steps:

1. Test the data roaming on another 4G device, such as a mobile phone, to verify if the issue is specific to the TP-Link 4G LTE Router or the SIM card.

2. Ensure that your TP-Link 4G LTE Router is using the correct APN profiles for the new mobile operator in the foreign country. The APN profiles determine the network settings required for data connectivity.