All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
There are different opinions of the scholars regarding a person who started fasting in one country and then travelled to another country where they started fasting later than the first country, whether he should continue fasting with the second country even if he exceeded 30 days from when he started fasting, or should he break the fast and not exceed thirty days.
An-Nawawi said: ‘‘If a person starts fasting in a country and then he travels to another remote country where the moon was not sighted at the same time as the first country, and he had already completed thirty days of fasting from the time he started, then, if we say that each country has its own ruling in regard to the sighting of the moon, there are two opinions about this:
If we say that the sighting of the moon applies to all countries, then the people of the second country are obliged to break the fast at the same time as the first country if the sighting of the moon was confirmed for them by the statement of that person or any other person, but they are obliged to make up for the first day. However, if this is not confirmed in the second country, then he (the person who started before them in a different country) is obliged to break the fast as if he was the only one who sighted the crescent of Shawwaal, but he should break the fast secretly.’’ [End of quotation]
According to our view in Islamweb, each country has its own sighting, therefore, the most correct opinion, according to Imaam An-Nawawi in this issue, is that if one travelled to another country where they started fasting later than his country, he is obliged to fast with them even if he fasted more than thirty days. However, he may break the fast secretly if he acts according to the second opinion which is also a considerable one.
To conclude, the scholars have different opinions about the issue, and whichever opinion one follows, he should not be blamed. Nonetheless, there is no absolute evidence from the Quran or the Sunnah of the Prophet about it.
Allaah Knows best.