Can I swap my sim card from an o2 iphone to a vodafone blackberry, and vice versa?

[jack]

I am planning to swap phones with my dad but we want to keep our sim cards. Can I swap my O2 sim card previously used in an iphone and put it in his blackberry that was bought and was used with a vodafone sim card? this applies the other way round too with the vodafone sim being put in the o2 iphone. Thanks in advance

 

[Gaby]

i think it would mostly depend on the phone line you have..because some phones dont need sim cards.

 

[idac123]

both phones need to be unlocked or sim free you can not change