Fishing -- If you want to try your hand at fishing for guapote, call Captain Ron at Arenal Fishing Tours ((tel) 2694-4678; www.arenalfishing.com), or just ask at your hotel. A half-day fishing trip should cost around $275 per boat, and a full day goes for around $375. The boats will usually accommodate up to three people.
Horseback Riding -- Any of the hotels in the area can hook you up with a horseback-riding tour for around $10 to $20 per hour.
Swimming -- You can swim in Lake Arenal, although it can get a bit rough in places, especially during peak windsurfing season. Up above Lake Arenal on the far side of the lake from Tilarán, you’ll find the little heart-shaped Lake Coter. Surrounded by forest, the lake has good, protected swimming. (UFO watchers also claim that this is a popular pit stop for extraterrestrials.) A taxi to Lake Coter costs around C15,000.
Windsurfing & Kiteboarding -- If you want to try windsurfing or kiteboarding, check in with Tico Wind ★ ((tel) 2692-2002; www.ticowind.com), which sets up shop on the shores of the lake each year from December 1 to the end of April. Rates are $92 per day, including lunch; multiday and lesson packages also available. This is also the place to rent stand-up paddle boards and equipment.
Wakeboarding -- Lake Arenal is a big lake with plenty of calm quiet corners to practice wakeboarding. If you’re interested in lessons, or just a reliable pull on a wakeboard or water skis, contact Fly Zone ((tel) 8339-5876; www.flyzone-cr.com). Simple pulls behind its specialized boat run around $135 per hour, including boards, skis, and any other necessary gear.