Is it worth bringing kids to the La Juanita fair? Yes: it's an open-air market with no entrance fee and no booking, and you can stay for ten minutes or the whole afternoon depending on the group's mood. That said, it only runs in season, so it's worth planning the visit for when it's actually open rather than assuming there are stalls every weekend of the year.
What to do
The heart of the fair is its stalls run by local producers and artisans: organic food, baked goods, pottery, textiles and design objects. For kids, walking between the tables looking at what's for sale is often enough of an activity on its own, especially if there's something to sample along the way, like a pastry or a handmade snack. You don't need to buy anything for the outing to be worthwhile: browsing works fine as an outing by itself. If your group wants more detail, the portal has a page on the La Juanita Fair with more on the stalls and the feel of the place.
Where
The fair sets up along Route 10 in La Juanita, around kilometer 164, between Punta del Este and Laguna Garzón, in the Maldonado department. There's parking right on site next to the road, so you won't have to walk far with kids from the car. La Juanita is just a few minutes from the Laguna Garzón circular bridge, so it's easy to combine a lagoon visit with the fair on the same day.
When
Each season's exact dates are published at the start of the year, and the fair typically runs Saturdays and Sundays, from 10 am to 6 pm or until sunset, between January and the end of March. Since the calendar shifts slightly from year to year, it's worth checking with the Maldonado Intendencia or the organizers before planning your visit, so you don't show up on a weekend when the fair isn't running.
Tips for going with kids
Bring cash: it's what most stalls use, though some accept bank transfers. With younger kids, a short twenty- or thirty-minute round of the stalls tends to work better than staying the whole afternoon: take it slow, stop at whichever stall grabs their attention, and don't force the full loop if the group loses interest. Since it's a busy market on peak-season weekends, it's worth holding little ones' hands as you move between stalls. After the fair, La Juanita is good for continuing the afternoon on foot around the neighborhood, with a bakery and other shops nearby, or heading toward the lagoon for a shore walk with kids or some family kayaking before heading home.