For maximum efficiency — especially on a tight “layover” timeframe — it just makes sense to combine your Blue Lagoon visit with your trip to or from the airport. One important caveat is that the Blue Lagoon requires reservations — so you’ll want to plan this out in advance. There are several good options, but the two best — different but equally good — are the Golden Circle and the South Coast. The South Coast has at least a day’s worth of sightseeing, and it’s also a good home base for visiting the delightful Westman Islands. Since the ferry to the islands can be cancelled in bad weather, this plan works well: Plan two nights on the South Coast.