Prasonisi, also known as Vryonisi,[1] is an uninhabited Greek islet, in the Aegean Sea, close to the northern coast of eastern Crete.

It is extremely small, measuring just 0.034 square kilometres (370,000 sq ft) in area.

[2] Notably, there is a shipwreck on the islet's southern side, over thirty metres beneath the sea; the ship itself is broken up and possibly buried but remains of pottery, including amphorae, have been reported.

[3] Various species of sea snail have been recorded living on and around the island.

The island itself is mostly covered by salt-tolerant plants.