In the following conditions, travelers can observe their fast and be sure of its validity.

If a traveler reaches his destination before noon and does not commit any of the invalidating fasts, his fast is valid.

A traveler's fast while traveling with the intention of fulfilling a vow is valid.

A person who does not know that a traveler's fast is invalid should fast, and if he realizes this ruling at the time of Maghrib, his fast is valid.

A traveler who begins his journey in the afternoon, his fast is valid.

In order to observe his fast, the traveler must begin his journey in the afternoon and intend to stay for ten days.