Inform the bank prior to go oversea.
You need to know the PIN number for the CC because most merchant shops oversea need you to key in PIN number when buying something there using your CC.

Also, according to my experience when i went for Eurotrip on 2014, having 2 different CC (both Visa & Mastercard) helps a lot.

This is a safety measure in case if either one of your card didn't work for some reason, the other card will.

Last tip, becareful not to lose your CC there.
and always save the bank international hotline number in your phone should any problem occur.