Abstract Proton exchange membrane fuel cell (PEMFC), as a representative of fuel cell technology, has attracted much attention for its huge advantages in transportation application. Water management has a significant impact on the lifetime and performance of PEMFC. This study numerically investigates the movement of a water droplet in a single serpentine flow channel of PEMFC with different U-turn designs. The transport characteristics of the water droplet are obtained under both low and high airflow speeds, respectively. It is found that the droplet can pass through the U-turn for large fillet radius, while it is stuck in the corners of the U-turn for small fillet radius. The water droplet is transported as a whole without breakup under low airflow speed, but it is split into small droplets under high airflow speed at the U-turn. Hydrophobic channel surface promotes water removal at the U-turn of the channel, but its effect is weakened under high airflow speed.