Question:
Honorable Sheikh Dr. Salah Al-Sawy, my question concerns the ruling on fasting while traveling and the concession of breaking the fast in Ramadan.
We know that a traveler has a special allowance or exemption to break their fast if the journey is long or physically demanding, such as a trip from New York to Cairo. However, some people may be able to endure fasting. Should they fast?
Answer:
In the name of Allah, the Most Gracious, the Most Merciful.
All praise is due to Allah, and may peace and blessings be upon the Messenger of Allah, his family, companions, and those who follow him.
Breaking the fast while traveling is a concession, and no one has said that it is obligatory for a traveler to break their fast or that they are sinful if they choose to fast—unless fasting causes them harm, in which case they are prohibited from fasting to avoid harm.
If a traveler is capable of fasting, then it is permissible and even preferable for them to do so. The timing of fasting for a traveler does not differ from that of a resident; it is from the break of dawn until sunset, according to the region they are in. It is not determined by the country they are traveling to or the country they departed from. Wherever dawn rises upon them, they must begin fasting, and wherever the sun sets, they are permitted to break their fast.
And Allah knows best and is Most High.
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Taken from fatawaalsawy.com