Located on the Osa peninsula in the southwest corner of the country, the Corcovado National Park is a 42,000 hectacre tropical wet forest harboring jaguars, sloths, crocodiles, macaws, tapirs and eagles. This is a remote park with difficult access and can be challenging for mountain bikes. The trails during rainy season are impassible due to slick clay.
The park has three entry points: La Leona, on the southeast corner near Carate; Los Patos, on the northern perimeter; and San Pedrillo, at the northwest corner, 18 km south of Drake Bay. You can hike or fly into the park headquarters at Sirena, a large research station set back from the beach, midway between La Leona and San Pedrillo (it has an airstrip). Theres also a remote ranger station at Los Planes, on the northern border midway between San Pedrillo and Los Patos. All are linked by trails. Entrance costs $6 and is good for the duration of your stay. The park is administered through the Osa Conservation Area headquarters in Puerto Jiménez.
The CNP does have a 25 mile hike-a-bike through remote southern section. An interestingmountain bike route is from the Sirena Station northeast past the Los Patos Station to the town of La Palma (32 km). Be prepared for chiggers in grassy areas
Here are some basic notes on driving in Costa Rica for the tourist. There is a myth about the quality of the roads and of VW bus sized pot-holes. This may have been true years ago, but on the main routes, this is no longer true. With that said, there are still numerous challenges for first time drivers in Costa Rica. First, do not expect much out of so-call “highways”, like the InterAmerican Highway. The fancy name makes the uninitiated think this is a major 4 lane divided, restricted access road. Well, yes, about 1% is. The rest is two lane (marginally), undivided, rural roads with tons of traffic constantly stopping, turning, passing or driving slowly. Like every other road in the country, you can expect to see on the road numerous unexpected cows, cyclists, pedestrians, bus stops, school crossing zones, dogs, mud slides, police check points, unannounced one-lane bridges, missing manhole covers, and, of course, a never ending stream of semi-trucks driving erratically fast. What you do not find on any roads is much signage. There are infrequent signs indicating the distance to the next town, and even more infrequent are road names or numbers (if at all), including even within major towns. To make matters worse, signs that used to exist are disappearing due to deterioration or theft. Also, do not expect drivers to use their head lights, even in a heavy rain shower, unless it is really dark. This makes passing in rain a game of roulette since you can't see the oncoming traffic. Speaking of dark, do not drive at night since the roads in some areas can be ruled by those under the influence of alcohol.
If you have to drive through San Jose, make sure to do it at dawn to avoid the horrendous traffic all day long, including weekends. Keep in mind several maps show highways passing through San Jose. This is not true. They end abruptly on the outskirts of town and you have to slug it out in a crazy stop-and-go traffic and many unmarked turns to get to the other side all day long. There are unsigned so-called by-pass routes around San Jose, but finding them can be a challenging game of trial-and-error, and they are only marginally better.
If you have to drive on the Nicoya Peninsula, you can expect to find generally better roads with better signage. However, there are numerous unmarked eroded road sides, especially over stream culverts. Do not drive at night. Watch out for the iguanas sprinting across the road.
A GPS unit can be helpful when navigating roads, however, the maps in Costa Rica were created using a special map datum. This datum is not usually available on GPS units but the road base maps were created with it. Therefore if you use the default WGS84 datum with a base road map on the GPS unit, you will always show a position being about 0.5 miles to the north of the road base map.
When picking up a rental car, make sure to check all the tires for wear, check the spare tire pressure, check the tire jack, and make sure to test the lock on the spare tire. It would be wise to quickly purchase a can of Fix-A-Flat.
Overall, Corcovado National Park is the 9th most popular mountain bike trail of all 16 mountain biking rides in Costa Rica.