Many of the churches of Ios are designated preserved as historic monuments mainly of post-Byzantine times, as they are typical examples of Byzantine architecture of Cyclades islands [Spartinos, 2004]. The churches of Ios designated preserved as historical monuments are:
1. Panaghia Gremiotissa, Chora
2. Aghios Ioannis o Prodromos, Chora
3. Aghia Aekaterini, Chora
4. Aghios Nikolaos- Lazarou, Chora
5. Panaghia Chrisopighi, Chora
6. Evangelismos, Chora
7. Aghios Nikolaos- Aghia Varvara, Chora
8. Aghios Nikolaos, Chora
9. Aghios Gheorghios, Chora
10. Timios Stavros or Stavrou, Chora
11. Panaghia Faneromeni, Chora
12. Aghios Vasilios, Chora
13. Aghios Andreas and Aghia Kiriaki, Chora
14. Aghios Ioannis o Theologos and Aghios Panteleimonas
15. Taxiarches or Theoskepasti, Chora
16. Esodia Theotokou (Metochi) or Panaghia Amorghiani, Chora
17. Panaghia Katholiki, Chora
18. Aghios Gheorghios, Port
19. Aghia Irini, Port
Local tradition says that the number of churches is 365, as the days of one year, a number that in the late 1960s greatly reduced, since that “most of them are voulismenes (destroyed) dilapidated or their traces are lost “.
The majority of family churches, built of stone and clay and destined, through the namesake saint, to protect the animals and the land of each family from the "evil eye", were scattered throughout the island.
The churches of Ios are adorned with precious pictures, works of famous painters, like Michail Damaskinos and Ioannis Skordilis, who in the 17th century persecuted by the Turkish knife, fled to the islands of the Aegean. The sanctuary of small churches ia used as an ossuary. Also, some churches were part of the countryside monasteries, such as Aghios Ioannis at Pyrgos and Panaghia at Palaeokastro.
Aghia Irini at the entrance of the Port, Aghia Theodoti at the homonym place, Panaghia at the Palaeokastro settlement as well as Aghios Ioannis at Kalamos and Psathi are considered the biggest churches outside the settlement.
Within the limits of the basic settlement are twenty-two churches.
The architectural style that prevails in the town of Ios, is the "Basilica dome", a style widely used in the East and in the West since the time of Constantine the Great until the time of Justinian. The name and style came from the common style of the Roman basilicas galleries, served as courts and forums. Some churches in Chora and the outskirts, and almost all the country churches, have the same “Basilica” style.
Morphologically we can divide the churches of Ios in three categories:
1. Rectangles shapes with no curve, no dome, no uplift, but with a great measure of humility and simplicity that works so it shall submit believers in the environment of the cave of Bethlehem.
2. The single-aisled churches, the most widely used inside and outside Chora. But there are some two-aisled.
3. Byzantine ones, with dome and cross.
The natives’ hospitality at their fests is unique, offering traditional local foods and delicacies. In every fest, the visitor may taste different recipes based on meat, which are cooked traditionally, at the event place, in a way that only the locals know. In all of the island’s fests, the fun begins with Greek island music and dance. Simultaneously, various traditional events, such as fires and spicy lyrics, are taking place , accompanying Klidonas.
More specifically, on June 24 we celebrate Saint John Klidonas at Pyrgos, on August 15 the Assumption of Virgin Mary at Gremiotissa at Chora, on August 29 Saint John Kalamos and Saint John of Psathi, and on September 8 the Birth of the Virgin Mary, at Aghia Theodoti and Paleokastro. There are also the smaller fests of Aghia Varvara, of Mersinia, of Saint George at Vourlidakia and Saint Vlassis, but not lacking in anything from the big fests.