While abroad, it is especially important to keep in touch with home
Of course, the main solution in this situation is to buy a SIM card from local mobile operators, but here a simple language problem may arise. Have you ever tried to buy some 'Vodafone' in Egypt? And don't try. You don't know what you will buy, what tariff will be on that card, and whether it will not turn out much worse. In addition, a 'little trick' of local companies is the requirement of a non-zero balance, which will lead to the fact that everything on that balance by the time you return home will simply go to the company.
It is practically impossible for a traveler to understand all the details. Finally, buying another SIM card is simply inconvenient unless your phone supports two at once.
Some tourists advise simply downloading a free ICQ for mobile. ICQ for mobile is a modification of the ICQ program specifically for cell phones. This type of communication turns out to be cheaper simply because you only have to pay for Internet traffic, and it is minimal in this case, so if you want to tell relatives or friends a lot, it is easier to launch ICQ than to make an expensive call.
This application can easily be found on the web by searching for the word 'ICQ'. This can be a really good solution, unless you need to call home. However, business contacts may require a call, preferably from your phone, possibly even a fairly long one.
In this case, it is better to agree in advance with your company to switch your SIM card to credit-based payment for calls. In this case, the company acts as a guarantor to reimburse the mobile operator for all expenses related to calls on this SIM card. This solution is dangerous only if the phone falls into the hands of an attacker, but even then, you and your employers will 'solve the problem'. This service is provided to legal entities by almost all major operators.
If the trip is private, you can save money through phone cards, which come in general direction (i.e., the cost of calls to all countries is approximately the same) and dedicated directions (when you can call a particular country at very low rates). It is best to learn about the features of such cards, of course, while still at home, consulting with more experienced and knowledgeable travelers.