As a knowledgeable travel expert, I'm delighted to provide you with a detailed list of the most popular tours in the La Fortuna and Arenal Volcano area of Costa Rica. These tours offer unique experiences and opportunities to explore the natural wonders of the region. Here are some of the must-try tours:

1. Arenal Volcano Hike: Take a guided hike through the Arenal Volcano National Park and learn about the volcano's history and geology.

2. Hanging Bridges Tour: Walk across suspension bridges nestled in the rainforest canopy, allowing you to admire the flora, fauna, and stunning views.

3. La Fortuna Waterfall: Visit the majestic La Fortuna Waterfall and enjoy swimming in its crystal-clear waters.

4. Arenal Hot Springs: Relax in the natural hot springs heated by the volcano, where you can unwind and enjoy the therapeutic properties of the mineral-rich waters.

5. Arenal Lake Boat Tour: Take a scenic boat ride on Arenal Lake, offering panoramic views of the volcano and surrounding landscapes.

6. Canopy Zip Line Tour: Experience an adrenaline rush as you soar through the treetops on a thrilling zip line adventure.

7. Rio Celeste Waterfall Hike: Venture to Tenorio Volcano National Park to witness the captivating blue hues of the Rio Celeste Waterfall.

8. Wildlife Safari Float: Drift down the calm Peñas Blancas River on a guided float tour, observing diverse wildlife such as monkeys, sloths, and birds.

9. Venado Caves Exploration: Explore the underground wonders of Venado Caves, navigating through narrow passages and encountering fascinating rock formations.

10. White Water Rafting: Challenge yourself with an exhilarating white water rafting experience on the Balsa or Sarapiquí River.

11. Ecotermales Fortuna: Visit a serene hot springs resort with multiple pools and natural settings, perfect for relaxation and rejuvenation.

12. Arenal Hanging Gardens: Discover a botanical garden with well-maintained trails, beautiful orchids, and a butterfly observatory.

13. Arenal Natura Ecological Park: Explore this ecological park featuring walking trails, a frog sanctuary, a serpentarium, and a butterfly garden.

14. Sky Adventures Arenal: Enjoy a combination of adventure activities such as zip lining, aerial trams, and hanging bridges.

15. Kayaking on Arenal Lake: Embark on a kayaking adventure across Arenal Lake, surrounded by stunning views of the volcano and the countryside.

These tours provide a diverse range of experiences, allowing you to immerse yourself in the natural beauty and thrilling adventures that the La Fortuna and Arenal Volcano area has to offer.