If you are already at Koman and you want the pebble beach, take the shared boat. The 09:30 boat is €20 per person and back at Koman at 15:45. The 12:00 boat is €25 and leaves the river at 17:00, so the stop is longer and the day ends later. Neither ticket includes the road from Shkodra.
The €38 ticket is the whole day from Shkodra: minibus from Migjeni Theatre at 07:00, the morning boat, and the ride back to the city. A private boat is €200, listed for up to 30 people, about five hours, and you choose the hour. The speedboat is €250, listed for up to 8, usually four to six hours. The one-hour cave tour stays near the port and the published price starts at €60. It does not go to the Shala River. The ferry is the car crossing to Fierza, €10 per passenger, and it does not stop for a swim.
Komani Lake to Shala River, 09:30 · Komani Lake to Shala River, 12:00 · Shkodra to Komani Lake and the Shala River · Private boat on Komani Lake and the Shala River · Private speedboat to the Shala River · One-hour boat on Komani Lake · Rozafa ferry, Koman and Fierza