1. Don't ignore/neglect beach safety
Costa Rica is certainly famous for its beautiful hundreds beaches perfect to surf. It is thus obvious to exercise common sense and understand basic safety rules. Many of the beaches have high tides, causing reckless locals and tourists alike to drown every year. Tides tend to be at their strongest from May to November. So, be very careful if you plan on surfing. Oh, by the way, don't bathe naked in any source of water at any time.
2. Don't rely on travelers checks
Travelers checks are not a bad idea, but they’re becoming a bit difficult to use when travelling world-wide. That said, it is even harder to use them in Costa Rica because they are not widely accepted, even in touristy areas. So, to avoid any hassle when paying the hotel or making your purchases, use cash and/or a credit card.
3. Don't ignore traffic/driving laws
It is said that Costa Ricans are some of the world's most impatient and least compliant drivers. During your stay, if you’re your own driver, you might want to take this advice seriously. A speeding ticket could cost you hundreds of dollars. Don’t phone or text, dont’t drink while driving. Police officers may not be everywhere, but there are mounted cameras that patrol the highways too.
4. Don't tip
After a delicious meal at a restaurant, you are not expected to tip the waiter/waitress, unless you receive exceptionally great service; because a service charge of 10% is already included in your bill on top of the tax. Taxi drivers also do not need to be tipped. In the other hand, you should tip hotel busboys and maids. You should also tip tour guides as they count on that because of the good job they do.
5. Don't lack respect towards nature
That one is a «don’t even think about it !» If you’re caught disturbing the fauna and flora or littering, you will be in deep trouble because it’s considered a felony. Costa Ricans are true protectors of the country’s biodiversity, so to them, disrespecting nature is a big no no ! It is strictly forbidden to pick, damage plants or flowers while hiking in the forests or anywhere else, hunt for seashells while at the beach, no matter how beautiful and irresistible they are.
6. Don’t take unofficial taxi
If you’re not your own driver and don’t want to take Uber or the public bus, it is strongly advised to not take unofficial taxi (they are called pirate taxi). Those drivers often tend to ripoff unsuspecting tourists. You should then rely on the official government licensed red taxis with the yellow triangle. Make sure the driver uses the meter by telling him: la maria por favor(the taximeter please). At the airport, only the orange taxis are authorized to pick you up.
7. Don’t feed the monkeys
For your own sake as well as theirs, it’s better to not feed the monkeys. One of the reason is that our food isn’t good for them. Other reasons are that monkeys can pass diseases unto humans and, visa versa. Sometimes, they can also be agressive, even if they seem tamed. They’ve been known to steal, snatch bags and even purposely pee on people standing under them.