Continental shelves/Mediterranean

Aegean Sea shelves
Humans first occupied the Franchthi cave (center of the red circle on the map to the right, located at 37°25'24"N 23°07'56"E) during the Upper Paleolithic, appearing around 38,000 BCE (and possibly earlier.)

Groups continued to live in or seasonally visit the cave throughout the Mesolithic and Neolithic eras, with occasional short episodes of apparent abandonment.

Along with Theopetra Cave, a similar prehistoric dwelling in central Greece, Franchthi stands out as one of the most thoroughly studied sites from the stone age in southeastern Europe.

During much of its history Franchthi was significantly further from the coastline than it is today, see the map on the left at about 37.5°N 23°E, due to lower sea levels that have since risen around 400 ft. Its inhabitants looked out on a coastal plain that was slowly submerged over the course of their occupation.

During the Upper Paleolithic Franchthi Cave was seasonally occupied by a small group (or groups), probably in the range of 25 - 30 people, who mainly hunted European wild ass and red deer, carrying a stone tool kit of flint bladelets and scrapers. Its use as a campsite increased considerably after the Last Glacial Maximum (LGM), with occasional hiatus in the sequence of occupation.

Obsidian from the island of Melos in the Cyclades some 130 km distant appears at Franchthi as early as 13,000 BCE, offering the earliest evidence of seafaring and navigational skills by anatomically modern humans in Greece. (There is evidence that suggests ancient mariners - such as Homo Erectus or Homo Heidelbergensis - may have reached Crete at least 130,000 years ago.)

Obsidian (a glass-like volcanic rock) from Milos was a commodity as early as 15,000 years ago (by obsidian hydration dating). Natural glass from Milos was transported over long distances and used for razor-sharp "stone tools" well before farming began and later: "There is no early farming village in the Near East that doesn't get obsidian". The mining of obsidian did not lead to the development of permanent habitation or manufacturing on the island; instead, those in search of obsidian arrived by boat, beaching it in a suitable cove and cutting pieces of the volcanic glass from the quarries.

An apparent break in the occupation of Franchthi cave occurred during the Younger Dryas climate cooling event. The Mesolithic is represented by only a few sites in Greece, and, like Franchthi, nearly all of them are close to the coast.

Crete
Hundreds "of stone tools [were discovered] near the southern coastal village of Plakias. The picks, cleavers, scrapers, and bifaces were so plentiful that a one-off accidental stranding seems unlikely. The tools also offered a clue to the identity of the early seafarers: The artifacts resemble Acheulean tools developed more than a million years ago by H. erectus and used until about 130,000 years ago by Neandertals as well."

Naxos
"Possible Neandertal artifacts have turned up on a number of islands, including at Stelida on the island of Naxos. Naxos sits 250 kilometers north of Crete in the Aegean Sea; even during glacial times, when sea levels were lower, it was likely accessible only by watercraft."

Hundreds "of tools embedded in the soil of a chert quarry [were uncovered]]. The hand axes and blades resemble the so-called Mousterian toolkit, which Neandertals and modern humans made from about 200,000 years ago until 50,000 years ago. These tools require a more sophisticated flaking method than Acheulean types do, including preparing a stone core before striking flakes off it."

"Other Paleolithic tools that appear to be Mousterian have been recovered on the western Ionian islands of Kefalonia and Zakynthos. The plethora of sites adds weight to the idea of purposeful settlement."

"People are going back and forth to islands much earlier than we thought."

Cycladic cultures
Cycladic culture was a Bronze Age culture (c. 3200–c. 1050 BC) found throughout the islands of the Cyclades in the Aegean Sea, with a relative dating system for artefacts which broadly complements Helladic chronology (mainland Greece) and Minoan chronology (Crete) during the same period of time.

"An uninhabited, seemingly drab landmass [islet of Dhaskalios, off Keros] some 10 kilometers from the holiday island of Naxos in the Aegean, has yielded 4,600-year-old structures".

"The intricate, interconnected and multi-level architecture gives a clear impression of a planned and well-built settlement."

"Constructed in the same period as Stonehenge and the Pyramids of Giza, the discovery indicates that the early inhabitants of Greece were influenced by a global trend of architectural innovation. During this time, pyramids were starting to become spiritual symbols in Egypt, and it was also during this time that Egyptian influence first became apparent in Crete."

Neanderthals or Homo heidelbergensis
In "Greece [optically stimulated luminescence (OSL) dating] has produced dates of over 400,000 years old. The sampling itself took place by moonlight… as exposure to the sun would ruin the process, having initially studied in detail the stratigraphy".