The eurasian hobby flies so fast that it is difficult for people to spot them. Even house swallows and swifts, which fly very fast, can be captured by them. Insects such as dragonflies, crickets, longicorns, and golden turtles are also preyed upon by the eurasian hobby in large numbers.

Eurasian hobbies are good at flying and hunting in open fields, but not at tracking prey in dense forests. They eat their preys when flying, and rest mostly in tall trees or on top of utility poles, being rarely seen on the ground.

When hunting, a eurasian hobby makes a short and piercing call. During the breeding season, they also make loud calls when the intruder approaches their nests. Only during courtship do eurasian hobbies show tenderness. After pairing, the male often brings food to the female. Then they fly around together, singing a soft "love song".