My grandma started getting me season passes here when I was probably a baby, and I came as often as I was allowed. I’ve probably ridden the roller coaster 100’s of times (including a time we got to come ride the roller coaster as many times as we wanted in a row as part of a class). There is also an adorable train that rides through the whole park and has great views, which I have witnessed numerous babies obsess over. This is the kind of “central hub” of the happening parts of the town. A lot of the other recommendations are adjacent to this.
You can party hard on the coves of West Lake (pictured above) or tool around the edges and ogle houses you could never afford (personal favorite) Or find a quiet area to take kids tubing. West Lake Okoboji is the deepest and cleanest lake, 6 square miles and maximum depth of 136’. It connects to the more shallow East Lakes (where I grew up). There are Marinas located literally everywhere, my childhood best friend’s dad has worked at Park’s Marina as long as I can remember, so would recommend them for rentals. They are located on East Lake, which I would recommend if you would like to do water sports and don’t have a massive boat (west lake can be choppy). You can go under The Trestle to access West Lake (amusement park area) from East.
See the website for trail info, but this is an old railroad converted to paved trail extending through all the nearby areas, around all the lakes, and up to Jackson, MN. The 14 miles through the central lakes area is called the Great Lakes Spine Trail. I have biked and ran these trails my entire life with my mom and brother, and they are well-maintained, scenic, and flat, bringing you past most of the local attractions.
Right on the water by Arnold’s Park and everything else, but kind of tucked away in a peaceful area. There is a museum, a big monument, and a pretty creepy mini-cemetery. This is the place we came on school field trips. I have not independently verified the information they present but it does seem a bit biased (like all white people descriptions of Native American massacres). Just had to add that. Regardless, it’s a short walk from the Park and in my favorite shoreline of the lake (great views of sunset)!
I came here as a kid, brought kids I nannied for here. There are your usual art exhibits (with local artists) but also they have this amazing interactive center for kids… with all the big machines where they can draw a massive cartooned self portrait, etc. Kids can spend hours here if you need a distraction, and I think it’s free or donation based. The trail around the pond out back is lined by local artist’s statues/exhibits, including my childhood neighbor’s art.