Immigration police received passengers on Israel-bound flights forced to return to Suvarnabhumi airport and allowed them to stay at either a hotel or the airport.
The move came as Iraq, Israel and Jordan all closed their airspace, affecting flights to Israel and nearby countries from Saturday evening.
Airport immigration police said on Sunday that El Al Israel Airlines informed them that it had to bring two Israel-bound flights back to Thailand due to Iran's attack on Israel.
The flights unable to reach Tel Aviv were LY82 (Suvarnabhumi-Tel Aviv) carrying 275 people and LY88 (Phuket-Tel Aviv) with 290 people aboard. They returned at 5.20am and 5.50am respectively on Sunday.
According to immigration police, passengers on such returning flights would normally have to stay at the airport because their passports were already stamped for their departure.
However, the Immigration Bureau let the passengers stay at the hotels arranged for by their airlines, especially elderly and young travellers.
The airlines will keep their passports and guarantee they will not illegally stay in the country.
Alternatively, the passengers have the right to wait at the airport so that they can hold onto their passports and avoid queueing up for the immigration process again.