Seonam Lake Park sits in the south of the city, nestled beside Hamwolsan mountain in Seonam-dong. It is a quieter alternative to the more central Ulsan Grand Park — a genuine neighbourhood park rather than a civic showpiece, and better for it. The lake is pleasant at any time of year but particularly so in autumn, when the surrounding hillsides turn amber and the reflections on the water are good.
The walking path around the lake takes about 30 minutes at a gentle pace. A cafe near the main entrance does reasonable coffee. This is the kind of place Ulsan residents come on weekend mornings to walk off the previous night, and visiting it gives a window into daily city life that more tourist-oriented sights don't. Reach it by taxi from central Ulsan, about fifteen minutes.