While not the most streneous hiking you'll ever do, hiking behind Traunkirchen can provide you with some of the best views of the town and the lake. Most of the trails lead uphill so the higher you go, the more you see. One trail of note is the trail to the 'Malerwinkel'. This litttle spot is known as the artist's corner. When you get there, you'll see why, though you may need to imagine a few branches out of the way! Take the time to really walk around. You'll find it worth your while!
Equipment: Clothing to suit the weather, good hiking shoes, and of course, your camera!!!
Scuba Diving is available in Traunsee, but be forewarned. You need to wear protective suits and also account for diving in altitude. Traunsee is located well above sea level so you have to adjust for that. The experts in Traunkirchen can surely help you prepare for your diving trip in Traunsee. From Traunkirchen, you can dive in at the Landhotel Traunsee. My apologies for the blurry picture!
Oh one note, I'm told you have to stay pretty shallow for most of the dive because below 10 meters, the water temperature is 4°C and your regulator can freeze on your cutting your air supply. A pony bottle or third regulator may be a good idea.
Equipment: Contact them to find out what you need to bring.