Four have been found in the last fortnight, including the discovery last week of a six foot long, 350kg turtle near Dunbar, East Lothian.
The reptile, an endangered species native to the Caribbean, was caught up in creel ropes and will undergo tests to determine its cause of death.
Experts at the Scottish Marine Animal Strandings Scheme (SMASS) said it was the fourth case of the species to be found dead off the Scottish coast during October.
Two weeks ago another leatherback turtle was caught in fishing lines off Drumbeg, Sutherland.
Other animals were found off the Isle of Coll and on the Isle of Skye, north of Elgol.
Matt Barnes, of the Marine Conservation Society, said: “We get a few strandings in Scotland every year, so it’s not that unusual. But to have four occurrences in such a short space of time is rather unusual.
“It’s a freak occurrence really. It could be bad timing or bad luck, because of the different circumstances.
“Two got entangled in creel lines and then subsequently drowned. The other two are still subject to research. We do not know their cause of death yet.”
The species is the largest of all living turtles.