How to turn your Samsung Galaxy S25 on or off

Press and hold the Side key until your phone is turned on.

0000

0000

If you're asked to key in your SIM PIN, do so and press OK. The default SIM PIN is 0000.

If an incorrect SIM PIN is entered three times in a row, your SIM will be blocked. To unblock your SIM, you'll need to key in your PUK. Sign in to the O2 website to get the PUK. Please note: If you key in the wrong PUK ten times in a row, your SIM will be blocked permanently. In this case, you need a new SIM from O2.

Simultaneously, press and hold the Side key and the lower part of the Volume key and keep them both pressed.

Press Power off.

Press Power off.