When you are travelling outside India, if you have wifi or a SIM of that country to get mobile internet, and using that to make Whatsapp calls etc, and you just need to receive SMS from India for some essential services such as One Time Passwords then read this.
You do not need to buy an international roaming pack just to receive SMS. Receiving incoming SMS from India to your mobile while you are abroad is FREE, you do not pay anything for that. You just need to have main account balance of around Rs 200/300 or so.
So whenever I need to use a service that sends an OTP to my Indian mobile number, such as while logging into my your bank account, I do this:
- Disable mobile data (important)
- Switch off mobile
- Remove foreign SIM
- Insert Indian SIM
- Switch on mobile
- Let it automatically search for & connect to a network in that country with whom my Indian mobile network has an agreement.
After I get network signal on the mobile I login to the service which needs to send an OTP and I get it instantly.