As I’ve written elsewhere, one of great things to do in Stockholm in the summer is to swim in the lakes and open water. When I lived in Sollentuna there were numerous opportunities. One of the ones that can be easier with children is to go swimming at Rösjöbaden.
Many of the swimming opportunities that abound in Stockholm are wonderful directly due to their informal nature, but sometimes, as all parents will know, it’s nice to have that type of experience, but with a few extra facilities or entertainments to keep the little ones happy. I’ve been to Rösjöbaden many times as both a couple and as a family and it works well on both counts.
As you can see from the photo here, there’s nice sand, good grass (and much more of it out of shot here) where you can happily have a picnic or a BBQ or play games with the children. In terms of water activities, there’s great swimming and an excellent tall diving board for the braver. Also out of shot is a large bendy slide which drops into a small swimming pool, toilets, changing rooms, shop and cafe. It’s also a campsite with cabins for those who want to holiday there.
It’s very accessible by either public or private transport and there’s some nice woodland walks in the woods next to the site itself. Being as it’s a commercial enterprise, you do have to pay a small fee for the use of some of the facilities, but that’s the trade off you make. You can read about the full facilities on their website (English and Swedish). In my opinion it’s probably not worth a trip up from central Stockholm (although it’s only 15km as the crow flies) as there are better alternatives, either closer or more well appointed, but if you’re already in the northern suburbs or thereabouts, it’s well worth a visit on a warm day.