This might sound like a silly question, but we are planning a move to Costa Rica, Cahuita/Puerto Viejo specifically. I have done extensive research and have also been to CR several times. What I've recently read was not to bring leather to CR since it is prone to mould. I initially assumed it means jackets. Now I'm wondering if leather furniture would also be a problem in the high humidity of Cahuita? Any advice or someone who has taken leather furniture to CR? Thank you very much for any advice!
I think that you should think twice about bringing leather furniture to the beach. If it is a controled environment with AC it might be fine, but I would not recommend that.

also check the arcr forum - association of residents of costa rica - this has been discussed many times there.
most people do not recommend bringing leather furniture because of the mold, as you said. if you are willing to do very regular cleaning, this would tend to stave off the mold. in my house, i have cushions on chairs and sofa that have covers i can take off and wash while i put the cushions out in the sun. no fun to lie down to watch a good soccer game only to find mold or mildew as your companion.
Leather furniture has a habit of coming back to life in this environment- give your sofa long enough and it will walk out the door and graze!

Wooden furniture with cushions on doesn't seem too comfortable though. Would upholstered furniture also become mouldy? Thank you for any advice!