If you must choose between Monteverde and Manuel Antonio, the good news is that they represent two complementary sides of Costa Rica. This guide helps you decide.
Climate and scenery
Monteverde is cool, humid and high-altitude: cloud forest, mist and unique biodiversity. Manuel Antonio is warm and tropical: white-sand beaches and coastal jungle.
Activities
Monteverde is known for hanging bridges, canopy ziplines and night wildlife tours. In Manuel Antonio, the national park combines trails with beaches, plus catamaran, snorkeling and kayaking.
Wildlife
Monteverde is ideal for birds (including the quetzal) and amphibians. Manuel Antonio is famous for sloths, capuchin monkeys and very close squirrel monkeys.
Budget and logistics
Both have options for every budget. Monteverde involves mountain roads; Manuel Antonio has more direct highway access.
Why not both?
Many itineraries combine the two: cloud forest first and beach to finish. The private transfer between them takes about 4 hours. See the Monteverde → Manuel Antonio route.