Jökulsárlón's quieter sibling — smaller, younger, and close enough to touch the glacier itself
Post-1950
Formed — decades after Jökulsárlón
~5 km²
Size
Free
No admission fee
Fjallsjökull
Its own separate feeding glacier
The Story
Fjallsárlón and Jökulsárlón look like they should be the same place — they're less than 15 minutes apart and both sit at the edge of the same massive Vatnajökull ice cap. But they're fed by entirely different outlet glaciers, formed decades apart, and genuinely tell two different stories. Jökulsárlón is fed by Breiðamerkurjökull and began forming in the 1930s. Fjallsárlón comes from its own separate glacier, Fjallsjökull, and didn't really start filling with water until after 1950 — younger, smaller, and considerably less visited.
The color tells you which lagoon you're looking at, if you ever see an unlabeled photo: Jökulsárlón mixes with the Atlantic through a tidal channel and runs bright blue; Fjallsárlón is pure freshwater, carrying more glacial sediment, giving it a darker, moodier tone. The glacier tongue here also reaches almost to the water's edge — you get a genuinely close, immediate view of the ice itself, rather than the more distant panorama Jökulsárlón offers.
As You Walk Around
Easy to miss if you're not looking
Look for a heart shape in the glacier ice itself. A natural feature in Fjallsjökull has been noticed often enough that it's become a bit of a local landmark — worth scanning for.
The triangular peak looming above the lagoon is Miðaftanstindur — its name roughly translates to "mid-afternoon peak," and its sharp, distinctive shape is part of what makes this spot so photogenic.
Watch for dark bands running through the ice. Those are compressed volcanic ash layers, evidence of eruptions from subglacial volcanoes buried beneath Vatnajökull — frozen records of eruptions nobody saw happen.
Fun Trivia
Things most visitors don't know
Travelers mix the two lagoons up constantly. Photos labeled "Jökulsárlón" online are sometimes actually Fjallsárlón — if you're familiar with the heart shape and the triangular peak here, you can usually tell the difference at a glance.
Before either lagoon existed, this was just a river valley. Around 1900, neither lake was here — just rivers running out from beneath the glaciers, simply named Jökulsá and Fjallsá. The lagoons only appeared once the glaciers began retreating and left space for meltwater to collect.