One of the best preserved castles of Greece is that of the New Navarino or Niokastro built during the Turkish occupation in 1573, to control the western coast of the Peloponnese.The name of the bay Navarino probably comes from the Avars who settled the region in 585-587 during the reign of Emperor Maurikius.In 1573 after the Naval Battle of Lepanto (1571) to secure more the natural port of pylos the Turks built a castle in the south entrance of the bay and through rocks and boulders the north entry (passage of the Fig) to make its water shallow. The new castle was named Niokastro opposed to older (Paliokastro) that rises to the north entrance of the bay.The Turks also built a stone aqueduct for the castle, length of about 1km originating from the source of Koumpe at Handrinos Village.

Opposite, a little farther from the city of Corinth, stands the imposing hill Acrocorinth.
On top, height 575 m is the ancient citadel of Corinth. It is one of the largest and oldest castles in the Peloponnese in a charming location to the sea and Attica. The access is from the Ancient Corinth.

Kastro is 6km from Loutra in Kyllini. This village owes its reputation to the nearby Frankish Chlemoutsi Castle standing on the hill dominating the village. It is 45km from Pyrgos.

The Frankish Castle of Karytaina was built in the mid-13th century on a steep rocky outcrop by Geoffrey of Briel.

It was one of the most important buildings in the Greek area during the Middle Ages. The castle is situated on the peninsula of Agios Nikolaos, has an ellipsoidal shape, with a length of 700 meters. Surrounded on three sides by sea, there is a small fort, Broutzi, connected to the main castle with an artificial stone bridge.

The castle of Bourtzi (Greek: Μπούρτζι, from Ottoman Turkish برج - burc meaning "tower"; formerly Καστέλι, Kasteli) is located in the middle of the harbour of Nafplio. The Venetians completed its fortification in 1473 to protect the city from pirates and invaders from the sea. The Greeks regained it from the Turks on June 18, 1822, from where they assisted in the siege of Nafplio. Until 1865 it served as a fortress. It was then transformed into residence of the executioners of convicts from the castle of Palamidi. From 1930 to 1970, it served as a hotel. Since then, it is mainly a tourist attraction hosting occasionally parts of the Summer Music Festival.

Old Pylos castle is a 13th-century fortress near Pylos, Greece. It is one of two castles guarding the strategic bay on which it sits; the other is New Pylos castle. It is also known by its historical Italian and Turkish names, respectively Old Navarino and Anavarin-i atik. Locally, it is simply Palaiokastro (Greek: Παλαιόκαστρο, "old castle"). The castle sits atop an imposing 200-m rock formation on the northern edge of the bay, flanked by sheer cliffs; the naturally defensible site has probably been occupied since classical times.[1] Although there are no physical barriers to access, the castle ruins have been declared "closed" because the structure is considered dangerous.

The castle located on the south summit of the hill called "Nissi" was built in the Medieval period and was later remodelled as a strong defensive complex. In the 18th century, the three Zapheiropoulos brothers, merchants living abroad, returned to their home town to fight for the Greek revolution and built their houses inside the caslte.
The 5th Ephorate of Byzantine Antiquities has restored the NW gate, the stairway leading to the central gate, and the crumbling sections of the enceinte.

Palamidi is a fortress in Nafplion, constructed in 1687 by the Venetians on a hill captured by them, after a fierce battle with the Ottomans during the Venetian-Turkish War. This hill has an altitude of 216 meters, you can go to the castle by foot via a staircase with 999 steps or by car throught the road. In 1715, during the last Venetian-Turkish War the Ottomans conquered it and blew up a part of it.

The castle lies on the prominent hill called "Larissa", overlooking the town of Argos. It was founded in the 6th century B.C. During the Byzantine period the fortress was of essential strategic importance and in 1203 came under the control of the archon of Nauplion, Leon Sgouros. In 1212 it was captured by Othon de la Roche and was controlled by the Greeks until 1388. Between 1394 and 1463 it was occupied by the Venetians. In 1463 it was captured by the Turks and remained under their control until 1822, interrupted during 1686-1715, when Larissa came under the control of the Venetian admiral Morozini. The site was liberated by the Greeks in 1822.