Stockholm is known for its archipelago which is split into three parts; the North, Middle, and South. This division helps when looking at timetables for the various boats, even if there are major routes through all of them too. In the far south, Utö is one of the major islands and well worth a daytrip. Try catching a boat which takes you the whole way in two and a half hours (summertime only), as otherwise you have to mess around with buses and commuter trains which is perfectly doable but involves warm buses and long waits when instead you could just glide through the archipelago.
An ancient landscape
People have lived on Utö since around 6th century due to its strategic position for sailors. The landscape here is quite dramatic. As you approach, you do so over an open stretch of water called Mysingen which is known for its naval activities, so do not be alarmed if you see a military presence out here. You usually arrive at the Gruvbryggan quay with bike rental, bakery and other services. From there you can decide if you want to stock up on picnic food and set off in almost any direction on the various paths starting here.
I recommend staying on the northern side if you only have a day. Head for the iron ore mines which opened in the 1100s since they were the life and blood of Utö for centuries. They closed in 1878, and now you can see the water filled shafts, here and there as deep as 215 metres so keep an eye on children at all times even if it is partly fenced off. Strolling around here gives you the opportunity to read up on the mining history in the museum (summertime), and see the mining village with its cottages. There is also a very impressive wooden windmill in this part of the island.
Swimming and dining
As you walk up to the mining village, you pass the huge wooden house which houses the island’s hostel, but there is plenty of other accommodation should you wish to stay the night. When you have reached the top of the hill and looked at the mine, Utö värdshus beckons you to stop. Even if you only visit the island for a few hours I definitely recommend lunch at the restaurant with a lot of history in what is the former mining offices. Today, it has a rather maritime feel to it, and if you sit on the veranda you have nice views to go with anything from champagne to classical Swedish home cooked food. In December when not much else is open on the island, this is where to go for cosy relaxation and a Christmas market weekend.
The northern part of Utö is made up of a lot of limestone which is hard to believe when looking at all the rocks and skerries around you, and considering the mine. It has been a nature reserve since the 1970s and has a lot of unusual flora. On the eastern side of the island are a couple of beaches, but you can also head to a more protected one just a short walk from the quay below the hill. Perfect if it is a hot day, or you are bringing children. Just make sure you do not miss the boat back!