With so many rivers running throughout the country, rafting in Brazil is an obvious choice. But the best time for floating a raft doesn't happen until closer to December, when the rain kicks in and rivers swell to capacity. But for the shoulder-season traveler going in the fall, there's hope yet. It's called the duck.

Duckies, those rubber, inflatable kayaks, made their way to Brazil in 1995 and now outfitters use them to introduce the adventurous to river kayaking the safe and fun way. These boats are stable and don't lock you in should you tip over. What's more, they're more maneuverable than a hulking raft, meaning you can take them out when the river runs low—or when things feel too dicey.

About 110 miles west of Rio you'll find Casimiro de Abreu, the put-in for ducking on the Macaé River. That river runs for about 50 miles toward the Atlantic and includes 15 rapids ranging from Class I to IV, and Rio Adventures (011.55.21.2705.5747; www.rioadventures.com) will have you bouncing along a four-mile stretch of it while spending a full day playing in the 65-degree water. The trip costs about $79 per person and includes equipment, transportation, and lunch at an all-you-can-eat buffet of Brazilian fare.