Driving in Costa Rica will likely necessitate a river crossing at some point. Unfortunately, too many travelers have picked up their off-road skills from watching TV, and every season Ticos get a good chuckle out of the number of dead vehicles they help wayward travelers fish out of waterways.
If you’re driving through water, follow the rules below:
Only do this in a 4WD, with 4WD turned on Don’t drive through a river in a car. (It may seem ridiculous to have to say this, but it’s attempted all the time.) Getting out of a steep, gravel riverbed requires a 4WD. Besides, car engines flood very easily.
Check the depth of the water before driving through To accommodate an average rental 4WD, the water should be no deeper than above the knee. In a sturdier vehicle (Toyota 4Runner or equivalent), water can be waist deep. If you’re nervous, wait for a local car to come along, and follow their lead.
The water should be calm If the river is gushing so that there are white crests on the water, do not try to cross. The force of the water will not only flood the engine but could also sweep the car away.
Drive very, very slowly The pressure of driving through a river too quickly will send the water right into the engine and will impair the electrical system. Keep steady pressure on the accelerator so that the tailpipe doesn’t fill with water, but go slowly; if driving a stick shift, go in first gear.
Err on the side of caution Car-rental agencies in Costa Rica do not insure for water damage, so ruining a car in a river can come at an extremely high cost.
For years Aeropuerto Internacional Juan Santamaría has suffered from a scam involving sudden flat tires on rental cars. Though it's commonly reported, it continues to happen.
It goes like this: after you pick up a rental car and drive out of the city, the car gets a flat; as you pull over to fix it, the disabled vehicle is approached by a group of locals, ostensibly to help. There is inevitably some confusion with the changing of the tire, and in the commotion you are relieved of your wallet, luggage or other valuables.
This incident has happened enough times to suggest that you should be very wary if somebody pulls over to help after you get a flat on a recently rented car. Keep your wallet and passport on your person whenever you get out of a car.