The number must be registered after reception.
Therefore download form
http://www.o2online.de/nw/assets/blo...istrierung.pdf
fill in, scan
with copy of your passport and send to
prepaidkunden-kontakt@o2online.de
Immediat activation is also possible by calling the customer service 0049-179-55282, but scan or fax of passport is required within a fortnight, otherwise the SIM will be deactivated.
Registration can also be done in the o2 shops in Germany