Photo: CHUNGHOI KIM / Unsplash
Silfra
Silfra is a water-filled fissure in Þingvellir National Park, about 60km from Reykjavík — under an hour by road. It sits on the Mid-Atlantic Ridge, where the North American and Eurasian plates pull apart at roughly 2cm a year; the current crack is generally dated to earthquakes in 1789. The water is meltwater from Langjökull glacier, roughly 50km north, which percolates through porous lava rock for an estimated 30 to 100 years before surfacing at Silfra. That filtration is why visibility is reported at 80–100m and often more — there is almost nothing suspended in it. It also means the water sits at 2–4°C (35–39°F) all year, so a drysuit is mandatory for divers and operators require a drysuit certification or ten logged drysuit dives in the last two years. The dive itself is shallow: 18m is the legal maximum, average depth is 7–12m, and a guided dive runs about 30–40 minutes through the four sections — Big Crack, Silfra Hall, the Cathedral and Silfra Lagoon. There is essentially no marine life. Bright green 'troll hair' algae is the main visible organism; dwarf char live in the deeper recesses and are rarely seen, and Arctic char come in from Þingvallavatn mainly during the August–September spawning period. Diving is guided-only through licensed operators, solo entry is prohibited, and a Silfra fee is charged on top of the tour price. Snorkelling is offered too, and is the option for anyone without the drysuit paperwork.
What makes it special
- The only place divers can swim inside the fissure between the North American and Eurasian plates, which separate at roughly 2cm per year
- Reported visibility over 100m — Langjökull meltwater filtered through lava rock for an estimated 30–100 years before it surfaces
- Four distinct sections in one shallow dive: Big Crack, Silfra Hall, the Cathedral and Silfra Lagoon
- The water is drinkable, and 60km from Reykjavík makes it a half-day trip rather than an expedition
Price range
$
Trip length
1–1 days
Diver level
Open water
Trip type
Day trip, Shore dive
Price is per person for a typical trip, excluding international flights ($ = under $2,000).
Silfra is a day tour, not a trip. A guided single dive from DIVE.IS starts around ISK 35,999 (roughly $260) and includes the instructor, all drysuit and dive equipment, and the Silfra entrance fee. Two-dive tours cost more. The Silfra fee itself is ISK 1,500 per diver or snorkeller and is normally bundled into the tour price. Þingvellir has no park entrance fee, but parking is ISK 1,000 for cars up to 5 seats and ISK 1,200 for 6–9 seats — relevant only if you self-drive rather than take operator pickup. Divers without a drysuit certification can instead book a 2-day PADI Dry Suit specialty course locally, at additional cost.
Best time to dive
- Current
- Mild
- Water temp
- 2–4°C
- Visibility
- 80–100m — Operators report over 100m of underwater visibility. The water is glacial meltwater filtered through lava rock for an estimated 30–100 years, so there is very little suspended matter. Visibility does not follow a season — it is the same all year. What changes is ambient light: summer has long daylight, winter dives are darker.
- Getting there
- Easy — Day trips from a coastal base, about 1.5h from the airport.
- Experience
- The rule is two-part and enforced by both the park and the operators. First, a diving certification equivalent to an Autonomous Diver — Open Water or above. Second, a dry suit certification (e.g. PADI Dry Suit Diver); alternatively, a logbook showing 10 registered drysuit dives in the last two years, confirmed in writing by an instructor from a recognised diving organisation. There is no 'guided drysuit orientation' shortcut for scuba: without one of those two, the options are a 2-day drysuit specialty course locally, or snorkelling instead. Minimum age is a source conflict — DIVE.IS lists 17 (parental signature under 18), Arctic Adventures lists 18. Operators require a medical statement, and participants over 60 need physician sign-off. Height and weight limits apply for drysuit fit (DIVE.IS: 150–200cm, 45–120kg). All dives are instructor-led; solo entry is prohibited.
Nearest airports
- KEF — Keflavík International Airport (Iceland's main international airport; about 50km from Reykjavík, and roughly 90 minutes' drive from Þingvellir. Most divers base in Reykjavík and take an operator day tour with pickup.)
- RKV — Reykjavík Airport (Domestic airport in central Reykjavík; relevant only for internal flights, not international arrivals.)
Permit required
Diving and snorkelling in Silfra are only permitted through licensed operators — solo diving is prohibited and you must always be with a buddy. Þingvellir National Park sells diving permits at its service desk. Park rules cap dives at 18m; deeper is prohibited. Divers must carry a drysuit; snorkellers may use a suitably thick wetsuit.
Silfra fee of ISK 1,500 per diver or snorkeller, normally included in the tour price. Þingvellir National Park charges no entrance fee, but parking is ISK 1,000 (up to 5 seats) or ISK 1,200 (6–9 seats), valid all day across the main lots.
Marine life
Sightings are never guaranteed — the bars show typical likelihood by month.
| Month | Likelihood |
|---|---|
| January | rare |
| February | rare |
| March | rare |
| April | rare |
| May | rare |
| June | rare |
| July | rare |
| August | occasional |
| September | occasional |
| October | rare |
| November | rare |
| December | rare |
Not a reason to book. Sightings are incidental — the dwarf char stay deep and dark, and the larger Arctic char come in from the lake mostly around the August–September spawning period. Most divers see no fish at all.
| Month | Likelihood |
|---|---|
| January | commonly seen |
| February | commonly seen |
| March | commonly seen |
| April | commonly seen |
| May | commonly seen |
| June | commonly seen |
| July | commonly seen |
| August | commonly seen |
| September | commonly seen |
| October | commonly seen |
| November | commonly seen |
| December | commonly seen |
Present year-round throughout the fissure; no seasonal peak. Most obvious in the shallow Lagoon where light reaches.
Dive sites
Worth knowing before you book
- The water is 2–4°C (35–39°F) every month of the year. Hands and face get cold fast, and there is no warm season to wait for.
- The drysuit gate is real: operators require a dry suit certification, or 10 logged drysuit dives in the last two years signed off by an instructor. No paperwork, no scuba — snorkel or take a 2-day course instead.
- There is essentially no marine life. Green 'troll hair' algae, rarely-seen dwarf char in the deeper recesses, and Arctic char mainly in August–September. This is a geology and visibility dive.
- It is short and shallow: 18m maximum by park rule, 7–12m average, roughly 30–40 minutes in the water for a tour that takes 6–7 hours door to door from Reykjavík.
- Guided-only through licensed operators, group sizes are capped, and tours book out in summer. Around ISK 36,000 (roughly $260) for one 30–40 minute dive is expensive per minute underwater.
Sources & last checked
Checked July 2026
This is a researched draft, not yet human-verified. The seasonality and logistics are drawn from the sources below — confirm specifics (permits, fees, closures) with an operator before you book.
- Diving — Þingvellir National Park — Þingvellir National Park
- Diving Silfra Day Tour in Iceland — DIVE.IS
- Dive Site Silfra in Thingvellir National Park, Iceland — DIVE.IS
- Diving Safety and Requirements in Silfra — Arctic Adventures
- Silfra — Wikipedia
- Parking Service — Þingvellir National Park — Þingvellir National Park
- How cold is the water in Silfra? — DIVE.IS
- Keflavik Airport (KEF) to Thingvellir - travel options — Rome2Rio
Note on the data: Minimum age conflicts between operators — DIVE.IS states 17 with parental signature under 18, Arctic Adventures states 18. Recorded as 17–18, operator-dependent; verify per booking. Wikipedia gives Silfra Hall a 45m maximum depth into a cave system and one operator page cites nearly 150ft (~45m), while Silfra's overall maximum is 63m; none of this is diveable recreationally, since the park caps dives at 18m. The 1789 earthquake date for the fissure comes from operator material rather than a geological survey. Coordinates are approximate fissure-level positions, not surveyed dive-site GPS. Prices are ISK as listed by DIVE.IS at time of research; USD conversions are rough and will drift. Water temperature: Silfra is glacial meltwater, not sea, and sits at 2-4C (35-39F) every month of the year because it is constantly fed from underground springs and never freezes, so a drysuit is mandatory year-round. Access: Keflavik International (KEF) to Thingvellir is about 1.25-1.4 hours by road; most divers instead base in Reykjavik (about 50 min from KEF) and reach the shore-entry fissure on an operator day tour, so there is no boat crossing. Independently verified 2026-07-20 (confidence high).