How to get there
We've been to Manuel Antonio national park a number of times and still enjoy it every time we go. The park is located at the e
nd of the road that leaves from Quepos and passes through the center of what is known as Manuel Antonio, though it is really a part of Quepos. The park is actually 134 kilometers from San Jose if you check your odometer but it will seem more like 200 kilometers. When you reach Quepos, you will wind your way through town trying to get to the back right corner of town where the road leads up the hill into Manuel Antonio. There are flights from San Jose on both Sansa and Nature Air that arrive into Quepos airport about 5 times per day. The flights cost about $145 round trip and baggage is limited to 26 pounds, especially if the flight is full. You can also get a driver or cab from San Jose for about $100 each way if you negotiate.
About the park
Manuel Antonio park is the smallest national park in Costa Rica but it is the most visited. Totaling about 1700 acres on land, the park was declared a national park in 1972. The park also consists of nearly 136,000 acres of marine reserve. I am always amazed whenever we go there at just how much wild life there is. We've had people in our real estate tour groups accuse us of staging the animals we saw. On our trip in November of this year, there was the biggest boa constrictor I have ever seen literally right at the entrance to the park. The rangers who collect tickets were not even bothering to collect the tickets since they did not want to be close to where the snake was. Since it is against the law to molest any of the animals in the park, they could not even shoo it away. We have seen every species of monkey in Costa Rica; howler, white faced capuchin, squirrel and spider monkeys. We've seen both two and three toed sloths, deer, pecurie, raccoon, turtles, hawks, pelicans, toucans, parrots, huge iguana, frogs, hermit crab, both red and blue land crab, coatis, amazing blue morpho butterfly's, caymen and more. We saw most while just sitting at the beach. In fact if you just sit in the shade of the palm trees by the beach and get there early, many animals will typically pass through sooner or later. The park's predominant feature is a peninsula of land that juts out into the ocean surrounded by sheltered coves on either side. The park is also home to a variety of species of mangrove including the blood mangrove with sap that looks like blood.
idyllic Beaches
One of the reasons for the popularity of the park are the beautiful white sand beaches. There are a variety of beaches but the most popular is is a sheltered bay 
that rarely sees any surf and is rings with coral formations on both sides. Beaches by name include Manuel Antonio beach, Puerto Escondido beach, north and south Expadilla beach and Playitas beach. The water is always the perfect temperate and Manuel Antonio park is a beach lovers dream. The beach areas are ringed with palm trees providing plenty of shade. There are showers (non potable water) as well as bathrooms at the beach. Facilities are primitive but were recently upgraded after it was discovered that untreated sewage was being dumped in the mangroves in the center of the park. The park also includes the islands around the park.
The rest of the story
There are reputed to be over 100 species of mammals within the park and 185 species of birds. (We've only seen 172 species so far). There are 12 islands that are all part of the park. The park is closed on Mondays so be aware and they also limit the number of people allowed into the park at any time so it is best to get 
there early. ON weekends and holidays there are long lines waiting to get in after about 10:00 am. Non residents pay about $10 entrance fee whereas residents pay around $3. There is nothing for sale in the park so bring anything you want to eat or drink with you. Also be sure to pack out any trash you brought in. It is illegal to feed any wild animal and they will throw you out of the park for doing so. The total walk from the new entrance to the old exit is about 1.25 miles and is easy for even the most athletically challenged. Wear comfortable shoes (walking shoes). There are a number of hiking trails that you can take in the park, one to a waterfall, one to a secluded beach cove and one to the top of a hill with a great overlook of the ocean. Your ticket allows you multiple entrance to the park for the entire day and you can leave and return. Be sure to bring a camera and binoculars if you have them. You might want bug spray if there early or late but during the height of the day I have never so much as seen a mosquito.
Should you hire a guide?
When you arrive at the entrance to the park there will be a bunch of guides looking for groups to escort. The cost of these guides is expensive by Costa Rican standards and for the most part not necessary. The guides that were hired will be visible throughout the park and it is easy to see what they are showing their groups. If you want to see everything by all means hire a guide. One really nice thing about the guides is that they have mono scope telescopes on tripods that can be used with most cameras allowing you to get really good photos of animals high in the canopy. All in all the park is highly recommended and should not be missed.