Can I read short messages when I change my mobile phone card?

If you change it in a short time, the message is still there, but if someone calls, it won't be displayed unless you send a message to inform you when you turn off your phone, but it will cost you. Generally speaking, SMS should be visible 24 hours after you switch back to your sim card. If you are worried that someone will call the original number, you can set up call forwarding!