The flippered animal was found stranded on Mellbystrand beach in Laholm in western Sweden.
Swedish broadcaster SVT, which was first to report the incident, said that the grey sea creature was a striped dolphin, the same species as two other dolphins washed up further along the coast in Onsala in February.
Kenneth Lundin, a marine biologist at the Natural History Museum in Gothenburg, described the recent findings as highly unusual and responded to speculation that global warming could be encouraging the animals to head to Sweden's relatively cold waters.
“It happens a few times a year, over the entire coastline. We have seen a slight increase, but we do not know if this is due to climate change,” he told SVT.
Dolphins are not uncommon in Sweden, but the striped species is usually found in much sunnier climes.
Top Swedish vets are now expected to examine the creatures to try and discover more about how they ended up in the Nordics.
In February, SVT broadcast the dissection of the first of the dolphins to wash up on the west coast live on breakfast television, causing plenty of Swedes to flip out on social media.
There was no sign of any animals going under the knife on Swedish news shows on Tuesday morning.