Platno Lake (, ) is the 410 m long in southwestâÂÂnortheast direction and 170 m wide lake on Long Beach, Nelson Island in the South Shetland Islands, Antarctica. It has a surface area of 4.2 ha and is separated from the waters of Bransfield Strait by a 40 to 110 m wide strip of land. The area was visited by early 19th century sealers.
The feature is so named because of its shape supposedly resembling a sail ('platno' in Bulgarian).
Platno Lake is situated at the base of Ross Point and centred at , which is 3.56 km southeast of The Toe and 3.4 km west-northwest of Vidaurre Point, the south extremity of the island. British mapping of the area in 1968.