Using a credit card in Greece/is a pin required?

I am not clear whether we need to have a pin to use a credit card the same way we use it in the U.S.

Do you mean a bank debit card the same card you use at the atm?
I have never needed a pin to use a credit card in the USA and only needed a pin for a debit card.
Either way the best and safest practice is to just use your credit card when you travel to pay for things and only your debit/atm card if you need cash.

Long before we had chips in our cards Europe moved to a "Chip and PIN" system for debit and credit card transactions. Europeans haven't signed pads or slips of paper in... nearly a couple of decades.

Being the American that has to sign slips is a PIA. Upgrade your cards to contactless and just tap to pay—it's the fastest, easiest, and is how almost everyone in Europe now pays for almost everything.

Addendum:

If you've gotten a new or replacement credit card in the last few years you likely already have a contactless card (only just becoming more common on US debit cards)—look for something that looks like a WiFi symbol on the card.

Contactless payment is increasingly common in the US, so you can try out "tap to pay" at lots of places.

Ok thank you. Perhaps I misunderstood something I read in another travel forum which gave the impression that you needed a pin to, say for example, pay for a restaurant meal using a credit card. Perhaps I misunderstood.

pjmun- Prior to contactless Europeans would use a PIN on the credit card machine, but Americans would still have to sign a slip.

There are occasional reports of problems in situations when there is no employee to deal with (such as at unattended gas pumps). There can be an issue there, because there's no way to collect your signature. In other situations, you'll often be asked to sign if you don't tap to pay, and even with tapping I think there may be an upper limit, above which you'll be asked to sign.

I've spent a huge amount of time in Europe since 2015, in 14 different countries, and I've only once been unable to complete a credit card transaction. I was trying to buy a bus ticket at a little vending machine on the street in Warsaw. Having US credit cards without PINs for purchases hasn't been a significant issue for me. Cards are different, so I cannot guarantee you will run into zero problems, but I think you will probably have no difficulties when you are dealing with a person as opposed to a machine. Some folks have said they got around a machine prompt for a PIN (when no employee was present) by entering 0000 or some random 4-digit number. I can't vouch for that, but I don't think it would hurt to try it.

Very helpful and reassuring. Thank you!

Out of curiosity, what is the objection to a Personal Identification Number (PIN)?

I don't have any objection but I was under the impression you needed one from your credit card company in order to use your credit card overseas and I don't have one. You have to request that from your credit card company and it takes 5-7 business days to receive it and we leave before that.

For most American credit cards, the PIN is only good for extracting money from an ATM. It is not used for regular transactions.

As stated, if you use the card by presenting it, you will have to sign a slip. However, with contactless you just tap and go. (Some countries put limits on how much you can use it for.)