Credit cards are generally a more secure method to pay for things and use at the ATM, as if there are any suspicions, your credit card provider should flag it and contact you, to clarify if the suspicious transaction was actually made by yourself. Some credit card providers will charge you for using there services overseas, so check before travelling. Debit cards are usually free to use from wherever you are in the world (excluding the use of a privately owned ATM, who may charge all users a fee for each transaction). Generally, debit cards are safe to use, however money can be taken from your account a lot easier than by credit card. So, you either use your credit card for secure transactions and possibly pay for the service, or use a debit card for free, but is not as secure as a credit card!