If you google “what to wear in Iceland," you’re going to get an overwhelming amount of information. I know I did. For me, the key to warmth and comfort is loose layers. This is what I wore on the trip, with notes on how I’ll do it when I go back:
Sorel boots with thick felt liners. These were perfect - warm, comfortable and waterproof. I love them. All of the reviews I read said to go down in size. If my boots ever wear out, I would even go down a half size more. I easily had room for 1 or even 2 thick wool socks plus wool liners. A liner is key with Sorel boots, which are rubber. Sweat can’t evaporate in the boots so having a liner and an outer sock helps wick moisture away from your foot. I’m a big fan of Sockwell wool compression socks so those were what I used as “liners.” I wore chunky Smartwool hiking socks on top of those and I was good to go. I did bring too many pairs. I think 2 pairs of liners and 2 pairs of socks were probably plenty for 8 days out in the field. That sounds gross, doesn't it? Only 2 sets of socks? But it's wicked cold and you don't sweat much. The wool helps to keep rank smells at bay and honestly, packing light is better overall. You'll likely be on the move every day or two, like we were, and having to re-pack all those extra clothes doesn't make a ton of sense.
Marmot Davos Soft-shell pants. These were expensive pants but so worth it. They fit beautifully, with the perfect amount of comfy stretch and a cute boot cut. They have cozy fleece on the inside too, which makes them yummy to wear next to the skin. Soft-shell isn’t exactly waterproof but the fabric pulls water to the surface, which keeps you dry without wearing crinkly waterproof pants. Our packing list recommended waterproof pants - and I brought them - but I didn’t wear them once. If I go back to Iceland again in the winter, I would only bring soft-shell.
Base layers. I brought 2 merino shirts and 2 merino leggings. One set was Ice Breaker and one set was Smartwool. Both were warm, and non-stinky. Next time I’ll still bring 2 shirts, since I wore one layered over the other, but I’ll only bring one pair of leggings. I also wore a pullover fleece every day. I had 2 with me, plus a wool sweater. Next time, I’ll bring just one mid-weight fleece and I’ll make sure it is a zip front jacket. Cooling off is far easier if you can just unzip all your layers.
Jackets. I vacillated here. I brought a Columbia shell with a thermal liner that has those heat-reflecting dots. It was cute but I hated it on the trip. It was too fitted and the arm gussets were too narrow. I hadn’t realized how restrictive it was until I had all my warm layers under it, and my back pack on. The thermal liner wasn’t all that warm, either, Next time I’ll bring a loser, longer shell with a Patagonia thermal liner.
Hats, scarfs and gloves. I brought the cutest wool ball cap with me. I wore it on Day 1 and then had to pack it away. It was warm but the winds in Iceland yanked it off my head every time we got out of the van. My “alternate hat" was a soft, knit, cashmere beret. That was a winner - it even fit under my ice caving helmet. I normally wear a scarf but I was worried that with a back pack and camera strap, a scarf would be twisty and choke-y. Instead, I brought a fleece neck gaiter. This was perfect since I often unzip my jacket a bit, and the gaiter kept the collar from chafing my neck or cheeks. The glovesI found were the best! The brand is called Freehands. They had pop-tops on the thumbs and index fingers which meant I never had to take my gloves off, could still grip my camera well and never had frostbitten fingers. On super cold days (or nights), I used chemical hand warmers which I highly recommend. They stay warm for hours. If you’re tired and cold, ripping open a pack of hand warmers perks you right up.
Ultimately, I found that the things that seemed like splurges - like the Marmot pants - turned out to be the most practical. After days of hard use, those pants still looked brand new. Conversely, my inexpensive Columbia jacket tore on Day 2. By the time I got home, it was trashed. I was initially concerned that I’d never wear all of this super warm gear again but after the Polar Vortex hit us in January, I practically lived in my Marmot pants and Sorel boots.