Costa Rica is a lush rain forest, and so has many rain forest and ecological related excursions. Our group chose to do the Canopy Tour Adventure which is zip-lining through the Costa Rican jungle. My wife, who had recently pulled a muscle in her neck, opted for the more sedate Sloth Sanctuary And Canoe Adventure. We all had a blast!

Here are the ones listed in the Carnival shore excursions book. Not all excursions will be available for every cruise, or during every time of year. Other cruise lines probably offer the same or similar excursions.
Excursions can either be booked through the cruise lines ahead of time, or while on ship. Booking the excursions directly with the operators is also an option. This can save you money, but involves risk if there is a problem.

Aerial Tram Tour (5 1/2 hours)
A Hacienda Experience (5 1/2-6 hours)
Tour a family owned farm.
A Taste Of The Tropics (4 1/2 hours)
Visit a pineapple plantation.
Biking Through A Caribbean Village (4 1/2 hours)
Banana Plantation & Coastal Highlights (4-4 1/2 hours)
Canopy Tour Adventure (5 1/2-6 hours)
Zip lining through the jungle.
Caribbean Train, Boat & Bus Experience (4 1/2 hours)
Costa Flores Tropical Gardens (5 hours)
Golden Bean Coffee Tour (6 hours)
Horseback Riding (4 hours)
Limon’s Fun City Tour (1 1/2 hours)
Off Road Adventure (4 1/2 hours)
Explore the mountains of Costa Rica in a Terra-X6 US military type truck.
Pontoon Jungle Ride (4 hours)
Rain Forest Kayaking (5 hours)
Rain Forest Wagon Expedition (3 1/2 hours)
Shaman’s Land Nature Walk (4 1/2 hours)
Sloth Sanctuary And Canoe Adventure (5 hours)
The Green Train (2 1/2 hours)
Ride a narrow guage jungle train from Limon to Bananito.
Tortuguero Canals (4 1/2 hours)
White Water Rafting (6 1/2 hours)