This is a combination of our two classic tours: The Lava Tunnel + Snorkeling the Silfra Fissure - the ultimate geological day tour adventure! Explore the lava tunnel & snorkel between tectonic plates in the crystal-clear waters of Silfra. Join both unforgettable experiences with this value-packed combo. Your day begins at The Lava Tunnel, where your expert guide leads you through a vivid underground world shaped by past volcanic eruptions. Equipped with all necessary safety gear, you’ll witness colourful mineral deposits, dramatic rock formations, and learn how Iceland’s unique geology carved this extraordinary cave. Next, continue to Thingvellir National Park, a UNESCO World Heritage Site and home to the famous Silfra Fissure. Here you’ll snorkel between the North American and Eurasian plates in glacial meltwater that has been naturally filtered through lava fields for decades, creating unmatched clarity with visibility reaching 100–150 meters. You can meet us directly at each location or choose the Reykjavík Transfer option for a seamless, no-car-needed experience. We’ll handle pick-up, transport between sites, and drop-off, so you can simply relax and enjoy the adventure.