Is it safe to visit the Blue Lagoon with the volcano erupting?+
When it is open, yes. The Reykjanes eruptions since 2023 have closed the Blue Lagoon and the town of Grindavík several times, and the lagoon reopens when the Civil Protection authority clears it. Check the lagoon's own site the day before you go; tours and transfers refund or reschedule if it closes. The eruptions have been fissure eruptions with slow lava, not explosive, and the area has been evacuated well in advance each time.
Can you see the volcano eruption site in Reykjanes?+
Yes, on a guided hike when access is open (/experience/620679/, /experience/938778/). You walk over or beside cooled lava from the 2021 to 2024 eruptions, black, cracked and still steaming in places. Whether you see anything glowing depends entirely on whether an eruption is active that week; most of the time you see fresh rock, not flowing lava. Routes change with the authority's guidance; the operator adapts the tour rather than cancelling.
What else is on the Reykjanes peninsula besides the Blue Lagoon?+
Quite a lot in a small area: the Bridge Between Continents over the rift, Gunnuhver's roaring mud pools and steam, the Reykjanesviti lighthouse cliffs, Krýsuvík's coloured geothermal field and the Kleifarvatn lake. It is lava all the way, treeless and often windy. Half-day tours (/experience/938778/) cover it from Reykjavík. It is the region people fly over and ignore, which makes it quiet.
Should I do the Blue Lagoon on my arrival day or departure day?+
Arrival day if your flight lands in the morning; a soak beats sitting in a hotel lobby waiting for check-in, and the transfer (/experience/1036423/) stores your luggage. Departure day if your flight leaves in the afternoon or evening (/experience/1036419/); it fills the awkward hours after checkout. Either way, allow three hours at the lagoon and confirm your entry slot matches the transfer timing before you pay.