Route 1 bends south from Reykjavík and traces the edge of Mýrdalsjökull, Europe's fourth-largest ice cap, passing sixty metres of freefall at Skógafoss and the walk-behind curtain of Seljalandsfoss within ninety minutes. These waterfalls are fed by meltwater from the glaciers that crown Eyjafjallajökull and Katla, both active volcanoes whose eruptions have repeatedly reshaped the coastal plain. The 2010 eruption of Eyjafjallajökull sent ash into the stratosphere and grounded aviation across Europe; its ice-capped summit is visible from both waterfall sites on clear days. The south coast road cuts through a landscape younger than most cities. Reynisfjara, the black sand beach near Vík, is composed of basalt fragments eroded from the Reynisdrangar sea stacks, hexagonal columns formed when lava met the Atlantic and cooled rapidly. The beach sits beneath cliffs of layered tephra and clinker, a record of eruptions dating to the settlement era. Sneaker waves and riptides make the shoreline hazardous; warning signs mark the high-tide line year-round. Forty kilometres east, Skaftafell sits within Vatnajökull National Park, a UNESCO site protecting outlet glaciers that descend from the 8,100-square-kilometre ice cap. Svínafellsjökull, one of the park's tongues, has retreated 2.3 kilometres since 1930, exposing terminal moraines and outwash plains now colonised by moss and Arctic willow. Jökulsárlón, the glacial lagoon at the terminus of Breiðamerkurjökull, opened to the Atlantic in 1935 after sustained warming caused the glacier to retreat inland. Icebergs calve from the glacier face and drift across the lagoon's 18-square-kilometre surface before passing under the Ring Road bridge and washing onto Diamond Beach, where transparent ice fragments rest on black sand. Seal colonies haul out on the ice floes between May and September. The lagoon has doubled in size since 2000; its maximum depth now exceeds 250 metres, making it Iceland's deepest lake. An iceland south coast day tour from reykjavik operates year-round, though winter departures often include stops at Katla ice cave, a seasonal formation within Kötlujökull glacier accessible only between October and March when meltwater channels freeze solid. South coast excursions from Reykjavík range from ten-hour waterfall-focused itineraries to fourteen-hour expeditions reaching Jökulsárlón. Departure times align with daylight hours: summer tours leave at 08:00 and return near midnight under the midnight sun, while winter trips compress sightseeing into the brief window between 10:00 sunrise and 16:00 sunset. Operators include glacier hikes, ice cave entry, and boat tours among their extensions, though each addition lengthens the day and reduces time at individual stops. Free cancellation policies expire 24 hours before departure.