Vífilsstaðavatn Lake is in Garðabæ. It's about a 20 minute drive from the center of Reykjavík. It´s popular with fishermen for small char and brown trout from April to September, but it´s a great place to let the kids out for an adventure too. There is a track around the lake which is approximately 2.5km. Its a gravel track which is fun to cycle around. Not so great for scooters.
Vífilsstaðavatn Lake and its surroundings is a nature reserve so you can´t take dogs between 15th April and 1st July and boats and kayaks are not allowed. Please don´t litter. There are several spots to Park.
(Parking and access to the lake is FREE)