While most of the world observes Purim on the 14th of Adar, Yerushalayim celebrates the holiday on the 15th of Adar. This is based on the fact that the Jews of Shushan, the Persian capital, also observed Purim on The 15th of Adar. The Shulhan Aruch (686:5) discusses the various conditions and circumstances that determine whether a visitor from a different city observes Purim on the 14th or the 15th .
The question arises whether there is a scenario in which a person would be obligated to observe Purim on both days-the 14th and the 15th . That is, what is the Halacha of someone from Tel Aviv, for example, who observed Purim on the 14th, who then travels to Yerushalayim on the eve of the 15th ? If he spends the night in Yerushalayim, would he have to observe Purim again?
There are different opinions among the Poskim. The Erech HaShulhan (Rabbi Yishak Tayeb, Tunis) held that Purim can only be observed once, whereas the Rama MiPano (Menahem Azariah da Fano, 1548-1620, Italy) held that a person would be obligated to observe Purim again, in this situation.
The Torat HaMoadim (p. 242) cites a contemporary precedent that clarifies this Halacha. From 1970-1974, Hacham Ovadia lived in Tel Aviv. After observing Purim there on the 14th, he would travel to Yerushalayim on the eve of the 15th , until the following evening. Nevertheless, he declined to read the Megila for the Sibbur, because he took into account the opinion that he was not obligated. However, he did read the Megila for himself without a Beracha, to fulfill the stringent opinion.
SUMMARY
If someone celebrated Purim on the 14th of Adar outside of Yerushalayim, and then travelled to Yerushalayim on the eve of the 15th, he should observe the Misvot of Purim again without a Beracha.
