Learn and perfect a foreign language
While you may not learn Spanish, French or Portuguese at an academic level, you lose all fear and barriers to spontaneous speeches in your environment when dealing with locals. This means that you will learn far beyond your school and university foreign language skills. Vocabulary, eloquence and, last but not least, grammatical rules are incorporated while you work on projects and are constantly in contact with people.
New contacts - friends and networks that often last for decades
Every new environment is a chance to meet people with whom you may remain friends for a lifetime. Especially during the volunteer work time, they show completely new perspectives and unknown insights into foreign cultures and ways of life. But often the contact persists beyond the period of the volunteer work, which creates interesting opportunities. For example, there can be visits, or you are invited yourself and have a contact person or even a place to stay in a country that you might want to visit again and again.
Better job and training opportunities through volunteering
Of course, you won't automatically become CEO of a company just because you've volunteered in the past. In fact, volunteering is an underestimated factor that can make a big difference. It signals characteristics that many employers expect from their employees. That is primarily the motivation to do more than the minimum in order to maintain one's standard of living. On the other hand, volunteering abroad shows empathy towards other people, animals and the environment.
Last but not least, volunteering abroad is attractive to universities. If you can prove voluntary work in your résumé, this has a significant bonus point compared to candidates who lack any voluntary or charitable work. Even with excellent grades and otherwise impeccable performance, volunteering abroad is an additional plus point at many universities, which can make the difference between acceptance and rejection.