"It's a tremendous feeling," Marcus Nord, one of the two divers from the expedition, told The Local.
"It's a really unusual thing to find and it was extremely unexpected by all of us."
Nord, who made a video of the dive (below), and his colleague found the dry cave when nearing the end of a 90-minute dive deep beneath the Jämtland mountains.
"We pulled out a little more line, headed a bit further in, and then my diving partner Stefan Barth saw a water mirror and poked his head through," Nord said.
There, roughly half a kilometre into Sweden's longest flooded cave system, the pair found a dry cavern measuring 15 metres in length, five metres in breadth, and nine metres in height.
The find was made somewhat more incredible as experts were unaware that any such cave existed in the mountain range.
The flooded passages themselves stem from a Norwegian river that flows under the mountain range for roughly three kilometres. However, both geologists and divers alike are still unsure exactly how much the tunnels twist and turn, and how many other similar offshoots there may be that are still undiscovered.
The divers have been working for six years as part of the Expedition Bjurälven team, only diving during winter when the water flow is slow and manageable.
Spelunkers worldwide have been quick to congratulate the Swedes on the discovery, which will be presented in July at a congress in the Czech Republic.
But as for Nord himself, he is just happy to revel in being part the ultimate goal of every adventurer.
"As an explorer, it's a lifetime fulfilling dream to find something like this. It truly is impressive," Nord told The Local.