It’s incredibly scary, but you never don’t feel safe. Our guide (Juan R) was awesome and very professional. Their whole setup (transportation from the hotels, their base in La Fortuna, traveling back and forth to the river) is quite efficient, and very well organized.
The rapids themselves are definitely a little intimidating for beginners, even though they’re on the tame side as far as rapids go. The first half of the journey is all rapids, then it calms waaaayyyyy down, and it’s pretty peaceful until the end. You will absolutely get wet, if not soaked, and there’s definitely a reason that all the rafts travel down the river together, waiting for each other to get thru tougher sections safely.
If you’re on the fence about doing this, it’s definitely going to push your limits just a little. But that’s the whole point of an adventurous vacation!