The waters off Manuel Antonio are in the Eastern Tropical Pacific, a migratory corridor for several whale species. Humpback whales are present almost year-round — Costa Rica has one of the longest humpback whale seasons in the world, with both northern and southern hemisphere populations passing through at different times. Blue and sperm whales have also been recorded offshore.
Several operators in Quepos run dolphin and whale watching tours, typically half-day trips on small boats. Spinner dolphins are the most reliably seen species. The best months for whales are July to October and December to March, though sightings can occur any time. Book with an operator who follows responsible wildlife watching guidelines — reputable boats maintain distance and do not chase animals.