Nepal Telecom (NTC) SIM can have roaming service. If you are going abroad you can subscribe the roaming service using USD code *1415*7# . But you cannot do this from abroad. If you are out of country you can subscribe this service via "Nepal Telecom" app.
To subscribe via app you need to go "Buy Packs" and then select "International Service" >> "GSM Prepaid Service" >> "Roaming Activation."
Though subscription successful, as of writing this the service has not been enabled yet.
Another option is login to selfcare portal of Nepal Telecom https://www.ntc.net.np/user/login if you have already created. Go to Buy Packages https://ntc.net.np/buy/packages and then select prepaid and then "International Services" and then under GSM Prepaid Roaming Service, the activation link can be found. This will send an OTP to mobile, so will not work outside the country.
roaming.support@ntc.net.np with the activation form, and citizenship scan copy to activate the service if you are out of country. Word file Download link |