Some providers offer roaming bundles, some allow you to use your plan's allowance when overseas for a set daily fee, while others let you roam on Pay As You Go Roaming rates, meaning that you pay per action (call, text, or data).
It can be a hassle to find out what your provider allows you to do in terms of roaming. In fact, I have spent hundreds of hours researching the roaming options mobile phone operators provide so that you do not have to.
New articles are being added every week, so come back if you cannot find your provider yet. You can even contact me if you want me to do the research for you.
For now, click on your country and find your provider. After reading the article, you will be an expert in roaming with your provider.