Remember, it's always possible to do laundry at your hotel or at laundromats in most towns. Depending on the airline, domestic flights sometimes charge $1 for every pound of lugage over 25 lbs., so if you're taking flights within Costa Rica it's a good idea to limit your non-essential items, or be prepared to pay extra.
Slim down the contents of your wallet or purse. Leave behind any unnecessary credit or debit cards.
Bring a passport and a driver's license, as well as a paper copy of each. Keep a contact list so you can have access to important phone numbers at all times.
We recommend bringing the following for 10 days or more of travel:
1 or 2 pairs of long pants
2 dress shirts
Long sleeve shirt
2 pairs of shorts
10 pairs of underwear
10 pairs of socks
Very light waterproof jacket
Sandals or flip-flops
Walking or running shoes
Lightweight casual shoes
Water shoes (especially if you have adventure activities planned)