Surface Area
84 km²
Iceland's largest natural lake, fed by underground springs and rivers.
Þingvallavatn - Iceland's Largest Natural Lake
Iceland's largest natural lake at 84 km², nestled in a rift valley within Þingvellir National Park. Home to the world-famous Silfra snorkeling fissure and four unique morphs of Arctic char.
Updated February 1, 2026By the Iceland.org Travel Team
Location
South Iceland
84 km² · Max depth 114 m · UNESCO World Heritage Site
Þingvallavatn fills a rift valley created by the separation of the North American and Eurasian tectonic plates. The lake's extraordinarily clear water is filtered through underground lava fields over decades before reaching the basin. Surrounded by the dramatic scenery of Þingvellir National Park, a UNESCO World Heritage Site, this is where Iceland's parliament (Alþingi) was founded in 930 AD. Today visitors come for Silfra's legendary underwater visibility and the haunting beauty of the tectonic landscape.
Safety + sourcing
Last updated: 2026-02-01
This guide is for trip planning, not emergency guidance. Conditions in Iceland can change quickly—always check official alerts and road conditions before you drive or hike.
Sources to check
Top Activity
Silfra Snorkeling
Snorkel or dive between tectonic plates in water with 100m+ visibility.
Access
Year-Round
About 45 minutes from Reykjavik via Route 36. Golden Circle stop.
What to Expect
Silfra Fissure
Snorkel or dive between the North American and Eurasian tectonic plates in glacial water with unparalleled clarity.
Tectonic Rift Valley
Walk along dramatic fissures and fault lines where the continents are slowly pulling apart at about 2 cm per year.
Arctic Char Diversity
Four genetically distinct morphs of Arctic char evolved in the lake after the last Ice Age, a phenomenon studied by biologists worldwide.
Historic Þingvellir
The lake sits below the site of the world's oldest existing parliament, founded by Viking settlers in 930 AD.
Fishing Opportunities
Licensed anglers can fish for brown trout and Arctic char in designated areas of the lake from May through September.
Scenic Lakeshore Walks
Multiple trails along the northern and eastern shores offer views of the lake, surrounding mountains, and volcanic features.
Getting There
Þingvallavatn is about 45 minutes northeast of Reykjavik via Route 36. The lake is a core stop on the Golden Circle route, and the Þingvellir National Park visitor center on the north shore provides parking, restrooms, and information. Silfra snorkeling and diving tours typically meet at the Silfra parking area on the lake's northern edge. The road is paved and accessible year-round, though winter conditions may require caution.
Best Time to Visit
Þingvallavatn can be visited year-round. Summer (June to August) offers the longest daylight hours and warmest temperatures for lakeshore walks. Silfra snorkeling and diving operate throughout the year since water temperature remains constant at 2-4°C. Autumn brings golden colors to the surrounding birch and the chance for northern lights. Winter visits offer a stark, dramatic landscape with fewer crowds. Spring sees the return of migratory birds to the lakeshore.
Planning help
Þingvallavatn FAQs
Quick answers with safety notes where it matters.