To efficiently collect Mystery Boxes in subway surfers online, you can follow these strategies:

Stay Alert: Keep an eye out for Mystery Boxes scattered throughout the level. They can appear in different locations, such as on platforms, in the air, or along the tracks.

Use Power-ups: Utilize power-ups like the Jetpack or Super Sneakers to reach higher platforms or cover more distance quickly, increasing your chances of collecting Mystery Boxes.

Upgrade Power-ups: Upgrade power-ups to extend their duration and effectiveness, making it easier to reach and collect Mystery Boxes during runs.