Why You Need To Check Whether Your Phone Works Internationally?
Basically, there are two types of phones you might have, especially if you've purchased it through a mobile carrier - GSM and CDMA. The latter ones won't be able to operate outside the US, while the first type or the two combined will allow you to use the phone abroad.
Also, in regards to the SIM card - some phones are locked, which means that they're only set to work with the carrier you've purchased the device from.
Therefore you will not be able to insert a local carrier's SIM when going on an international trip.
How To Save On International Phone Calls?
Having said that, if you're all good with your phone, we have several tips to make sure you're saving as much as possible on international phone calls:
Bring your phone with you, and purchase a new local SIM card to avoid global data roaming.
You can purchase a local SIM card of the country you're traveling to pretty easily and save quite a bit since many countries in Asia and East Europe can get you a ton of data usage and calls. Obviously, prices and condition vary, so you'll need to check that beforehand.
The main downside is that you will not be able to contact people back home because that would still qualify as international roaming with these SIM cards.
Therefore your only way of communication is social media.
Leave your home SIM card in, and only rely on WiFi without international data roaming.
While this option seems the most simple and straightforward, it presents some logistical and safety issues, since you're using public WiFI.
First of all, in case of an emergency, you might not be able to get to the nearest WiFi spot fast enough, and even if there's no immediate need, you're still going to need to plan your route keeping the Internet access points in mind.
Switch to international cell phone carrier with global roaming options.
The best option you can make is switching from a regular carrier to the best phone plans for travel. They are usually offered by international cellphone carriers. Most international cell phone plans provide you with cheap phone calls and data usage abroad.