You should plan to spend at least two full days in Manuel Antonio. You need between a half day to a full day in the national park alone. That night, you could go on a night tour of the jungle. During your second day, you’ll have to take your pick between some of the best activities in Manuel Antonio, like ziplining or kayaking, or day-tripping to Nauyaca Waterfalls. That said, you could easily spend one week in Manuel Antonio if you want to spend more time relaxing poolside or at the beach.