Reviving during a run, purchasing outfits and board upgrades
Collecting it while running and receiving it from mystery boxes and watching daily video
Tapping on the 'Save Me' button after crashing
Keys are a utility in Subway Surfers used for many things. Most importantly, keys are used to revive your character for 1 key, and the cost doubles over time. Keys are also used to unlock special outfits for many characters. They can be found while running, or in a Mystery Box, or from the Weekly Hunt. You can also buy different amount of keys; though you have to pay real money. As for the appearance of the key, it is light blue with a white outline, and has a star in the middle of the handle. It is the same star that is on the coins.
Where to Find Keys?
Watch the daily video for the first time (2 keys).
Watch the daily video for the second time or more or obtain from the Mini Mystery Box (up to 2 keys, rare).
Collect keys in a run (1 key).
Obtain from the Super Mystery Box or Mystery Box (up to 3 keys).
Complete the Weekly Hunt (regularly 10 keys).
Connect to Facebook (10 keys along with other gifts).
Buy in the shop (up to 650 keys for $100).
Introduction alert (5 keys).
How to Use Keys?
Buy outfits for characters.
Buy special powers and styles for hoverboards.
To revive after a run (1st revive consumes 1 key, consecutive revives consume double the amount of keys from the previous amount).
In the London edition, the Holiday Video was added, allowing the player to receive 2 keys once he/she watches the whole video. But after that edition, it was replaced with the Daily Video, but with the same function.
They are quite a rare item to be found during a run, even rarer than a Weekly Hunt token.
This fact makes the mission "Collect 2 (or 3) keys in one run" extremely hard.