we are going to costa rica on dec 22nd and plan to do some hiking and the two day savegre river rafting trip. I have read about bring long pants for hiking. is this a must. what can we expect regarding mosquitos at this time of year.
also any advice as to which zip line is best at arenal volcano. thanks

I'd recommend two things:

Fist, pick up a pair of nylon pants that zip off and turn into shorts. So if you get hot and the mosquitos aren't bad you have the option of wearing shorts.

Also, I'd recommend picking up bug spray with deet (at least 10%). It's a little stronger than what you'd get a pharmacy or supermarket. You can get it any camping/outdoor store or online.

Have a great/safe trip.

No Worries

Mike