This is a self-drive loop, so collect a car at the airport; it is roughly a 45-minute drive into Reykjavík. Two things to fix in your head before you set off. First, the season: this itinerary assumes the autumn shoulder, roughly late August to early October, when the roads are almost all still open, the driving is manageable, and the nights are just dark enough for a chance of the Northern Lights. Second, driving here is not like home — weather turns fast, so check road.is for conditions and safetravel.is before any longer leg, and a standard 2WD is fine for this whole route in that season (you would only need a 4x4 for the highland F-roads, which this trip deliberately avoids). Book flights →

Base yourself in central Reykjavík for the first three nights; everything on days one to three is an easy day-trip radius from here. Drop the bags and sort out swim kit — you will be in and out of geothermal water most days, so a quick-dry towel and flip-flops earn their place. Search hotels →

Skip the Blue Lagoon entirely and start instead at Sky Lagoon, an oceanfront geothermal lagoon about 15 minutes from the centre in Kópavogur, with an infinity edge that drops straight towards the North Atlantic. It runs a seven-step Icelandic bathing ritual (the Skjól), including a cold plunge and sauna; the basic Saman package starts at around 12,990 ISK (roughly £75), depending on the time slot, and includes a towel. It is still a built spa rather than a wild pool, but the setting is genuinely lovely at dusk and it eases you into the week. Book a time slot in advance.

Wander back into the centre for a first Reykjavík dinner — the streets around Laugavegur and the old harbour are thick with good places, from Icelandic lamb and fish to the famous harbour hot-dog stand if you want something quick. Keep it easy; you have an early-ish start and the Golden Circle tomorrow.