Fuschlsee, the Land Salzburg lake closest to Salzburg, lies 31km (19 miles) east of the festival city, reached by Route 158. The fact that there isn't much to do in Fuschl is the very reason it's so crowded with Salzburgers on weekends, who come to relax by the beautiful lake, and eat and drink in the taverns. Lake Fuschl is ringed by woodland, some of which comprises a nature reserve. The lake, lying to the northwest of the larger Lake Wolfgang, is only 4km (2 1/2 miles) long and less than 1.5km (1 mile) wide. Fuschl, strictly a summer resort, is on the eastern strip of the lake, across from Hof Bei Salzburg.
You might choose to stay in Fuschl am See as an alternative to Salzburg at any time of the year, but it is especially worth considering during the festival season. From here you can also explore Wolfgangsee.