[2][3] The complex includes also the islets and rocks of Diakopo, Diaplo, Karavi, Kastrino, Leipso, Ostrako, Plaka, Plateia and Tracheia.

Hyla arborea, Mauremys rivulata, and Malpolon insignitus were only found on Ereikoussa, and Lacerta trilineata only on Othoni.

Othonoi (Greek: Οθωνοί, Italian: Fanò or Othoni) is the westernmost point of Greece and the largest of the Diapontian Islands.

It is the northernmost island in the group, almost equidistant from Corfu to the southeast, Mathraki to the southwest, and Othonoi to the west.

It has two beaches, Porto (Πόρτο) and Braghini (Μπραγκίνι); the names are of Italian origin, and date back to the period of Venetian rule.

Mathraki (Greek: Μαθράκι, older form: Μαθράκιον) municipal unit has an area of 3.532 km2 and population of 329 (2011).

Mathraki is a quiet island that manages to stay clear of tourists except for the occasional hikers that brave the rocky coastline.

In his letter he stated that on April 19, 1383 granted the usufruct of Othoni Ereikoussa, Mathraki, Diapolo and Vido, the knight Theodore Skaliti as fief.

[9]: 29  In 1537, the Turkish fleet under the command of Greek origin pirate and admiral Hayreddin Barbarossa massacred the inhabitants of Othoni island after a long battle.

In Stavros district at an altitude of 217 m. a white stone cross exists until today to commemorate that event.

Dated after the Battle of Nafpaktos in 1571, when the Turkish fleet was destroyed and the islanders began to move more safely.

[9]: 30  In 1815, the English conquered Othonoi and as is said, sent to the island sick soldiers to recover because of the good climate that prevailed.

The Treaty signed on March 29, 1864 between the three powers (England, France, Russia) and the Kingdom of Greece, the Ionian Islands -and Diapontian islands- passed definitively to Greek sovereignty on 21 May.

There were also many ship owners as they had a large number of yachts and commercial steamships traveling to many Mediterranean ports.

[10] Unfortunately, within these decades of history that Diapontians wrote at sea, there were some victims because of several wrecks due to sloppiness and carelessness of those responsible in the last century.

[12] According to mythology, in the ancient times, Othoni was the island of nymph Calypso, who lived in a large cave.

[9]: 21–22  According to Hesychius, after the Trojan War, Elephenor, king of Avantes from Euboea fled to the island after the fall of Troy, to atone as he had killed his grandfather, Abas.

and it's a common opinion that their roots seem to be Epirotic, Arvanitic, Aromanian and from Paxos without forgetting the Italian and Venetian influence.

The main point of view of the most Diapontians the last century is that families from Paxos and Epirus immigrated Othoni.

In Montgomery, Alabama the house of one Othonian seaman called Alexandros Markou Kasimis was designated by the US authorities as a preservable monument as it seems that he was one of the first Greek immigrants in USA.