I want to hike the Fimmvorduhals hike, but I’d like to do shorter hikes first to prep. I know the national park has many hikes, but can you recommend a special route? Like a full day one, preferably.
There are several beautiful hiking trails in Skaftafell, but my favourite one is the hike up to Svartifoss waterfall which takes ca 90 minutes back and forth from the Visitor Centre. I have written a blog about my hike up to Svartifoss https://guidetoiceland.is/connect-with-locals/regina. You can take a detour on this hike up to Sjónarnípa viewpoint which will add a couple of km to the hike. There is a turf house which you can visit on the way back on this hike, called Selið, which is lovely to visit. This is a really beautiful hike. There is another shorter hike to Skaftafellsjökull glacier on a trail from the Visitor Centre. You can get very close to the glacier on this hike, but dress warmly as the temperatures drop so close to a glacier. Never hike on a glacier though without an experienced guide. If you want to go on a hike on Svínafellsjökull glacier, which is the glacier next to Skaftafellsjökull glacier, then there are several guided tours you can join https://guidetoiceland.is/book-trips-holiday/day-tours/from-skaftafell?a=135
Just to let you know, Fimmvörðuháls hike is between Skógar and Þórsmörk, so it’s pretty far away from Skaftafell. Like Regína pointed out here above then there are plenty of nice hikes in Skaftafell, such as the one to Svartifoss. There are also nice, shorter hikes not far away from Reykjavík, such as the hike up to Glymur waterfall in Hvalfjörður, or the hike to Reykjadalur hot river from Hveragerði.
The hike to Svartifoss is much shorter than the hike over Fimmvörðuháls.
Fimmvörðuháls hike can take up to 8-12 hours, depending on how fit you are. Some people even spend the night in a cabin along the way (that needs to be pre-booked) and hike it in 2 days. I have hiked it 3,5 times and always just in 1 day (the half time was when I only hiked half of it to Eyjafjallajökull to see the volcanic eruption, and then went back the same way I came and didn’t go the whole way to Þórsmörk). Twice I hiked from Skógar to Þórsmörk, and once from Þórsmörk to Skógar.
Going from Þórsmörk was much quicker as it’s first very steep uphill, but then gradually slopes down to Skógar and you can pretty much jog that part. Hiking from Skógar you’re gradually going uphill, for a very long time (along an endless amount of waterfalls!) which gets you pretty exhausted, and then there’s a very steep, but absolutely gorgeous, path downhill to Þórsmörk. Be careful.
You should not attempt to hike Fimmvörðuháls during wintertime, (the Eyjafjallajökull eruption was in March and it was COOOOLD, people could easily die up there in wintertime when no-one else is around. Þórsmörk which is at the end of the hike is also closed during wintertime, so you would need to hike the same way back to get out of there).
Be sure to be dressed well even if you hike it on a nice day during summer. You will be crossing a glacier and going past a volcano, the weather can be drastically different on top of the mountain than by the start of the route. Wear fleece and wool and avoid wearing cotton or denim.
There are not many options to fill up your waterbottle along the way, especially not when you walk past the volcanic bit, so bring at least 1 litre bottle and fill it up whenever you can. Either bring a tent with you, or book accommodation in Þórsmörk for when you arrive at the end of the hike. No food shops are along the way, so make sure you bring enough food to last you for the hike, and for the following day or days you’d like to spend in Þórsmörk. You can also pay a small amount to send food to Þórsmörk with a bus from Reykjavík if you plan ahead, and then you’ll have food with your name on it waiting for you at the end of your hike (great to send heavy stuff such as coals for a bbq and some steaks/potatoes/salad that you don’t want to carry the whole way!)
A bus leaves Þórsmörk at least once a day during the summer season that can take you back to Reykjavík (or to Hvolsvöllur or Hella if you prefer).
Hope this information helps