Debit Card

You’ll be able to use it as a Visa/Mastercard, no problem. I would suggest updating your card to contactless, if it isn’t already.

The one hiccup is that you’ll probably be charged a foreign transaction fee of 2-3% by your bank.

Make sure to put a travel alert on the card, if your bank needs one. This can be done online.

If you have time, I would go ahead and get a "No Foreign Transaction Fee" (FTF) credit card, Visa or Mastercard branded, and likely it will be Contactless enabled, which is important.

If nothing else, then you would have a back-up, I do not travel without at least two credit cards and a couple Debit/ATM cards.

Will not recommend a specific card, but several from Chase and Capital One offer no FTF and no annual fee, if you bank at a Credit Union, they likely offer one as well.

Assuming that your debit card uses either the VISA or MASTERCARD networks (Plus or Cirrus), you will be fine. Discover card are less widely accepted. Personally I would try to open a visa branded card to give max flexibility. To keep ourselves well covered we take two debit cards tied to two different accounts and three credit cards. Our primary debit card is from a credit union.

You could have an unexpected emergency, and have to buy airline tickets home, spend time in a hospital, have to pay for hotel rooms (which put a hold on your card) rent a car, or anything with a high price tag. Will you be able to cover that with your debit card?

I would not travel anywhere without a usable credit card.

I'm a solo traveler. I belong to 2 credit unions. I have credit and debit cards for both. I use the debit cards strictly to get cash from cash machines affiliated with banks wherever I am. I use the credit cards to pay for things directly. Neither credit union charges any fees for any of the transactions.

My recent experience is that credit card use is much more common than cash. My credit cards are both tap to pay. Last summer I literally tapped my way through the Republic of Ireland, Northern Ireland and Wales.

Considering that it's been so long since your last time in Europe, I highly recommend that you devour the Travel Tips here on this RS website: https://www.ricksteves.com/travel-tips

Some of the info on money seems to be a bit dated. However, to me these points are very important to your question:

From Using Credit cards in Europe:

"Dynamic Currency Conversion: Just Say No

Some European merchants and hoteliers — capitalizing on the fact that some Americans are intimidated by unusual currencies — cheerfully charge you for converting your purchase price into dollars. If it's offered, refuse this "service" (called "dynamic currency conversion," or DCC). You'll pay extra for the expensive convenience of seeing your charge in dollars. The price is usually based on a lousy exchange rate set by the merchant's bank — and even though you're paying in "dollars," your credit-card issuer may still levy its standard foreign-transaction fee.

DCC charges are common all over Europe; in some countries major banks require merchants to offer it. If you're handed a receipt with two totals — one in the local currency and the other in US dollars — circle the amount in the local currency before you sign.

According to Visa and MasterCard, consumers have the right to decline DCC service: If your receipt shows the total in dollars only, ask that it be rung up again in the local currency. If the merchant refuses to run the charge again, pay in cash, or mark the receipt "local currency not offered" and warn the clerk that you will be disputing the charges with your bank.

Some ATM machines also offer DCC, often in purposefully confusing or misleading terms. If an ATM offers to "lock in" or "guarantee" your conversion rate, choose "proceed without conversion." Other prompts might state, "You can be charged in dollars: Press YES for dollars, NO for euros." Always choose the local currency."

From Bank Safety Tips for Travelers:

"Don't use a debit card for purchases. Because a debit card pulls funds directly out of your bank account, potential charges incurred by a thief are scary — it's your money that's gone, and it will stay gone until the fraudulent use is investigated by your bank. For that reason, I limit my debit card use to cash-machine withdrawals. To make purchases, I pay with cash or a credit card."

You might enjoy the info on Copenhagen: https://www.ricksteves.com/europe/denmark/copenhagen

I was in Denmark as part of an RS Scandinavia tour in 2018 and used almost no cash at all except to do laundry on Ærø.

I know nothing about Lithuania except that I have a friend with dual USA/Lithuania citizenship. I'd guess that they are as advanced as the Scandinavian countries, but that's pure speculation.

We travel with 2 ATM cards from separate financial institutions and 3 no foreign transaction fee from Visa, MC and Amex. The problem you have with one card is that if you have an issue and it no longer works you are very much in a world of hurt. At least you need a NFTF Visa card to go with your ATM card.

I would check double check with you bank on the ATM card - I have heard, some debit cards do not work in Europe.

As long as your debit card is tied to either the Plus or Cirrus networks your debt card will work fine. I have not heard of debit cards not working in Europe. Sometimes it will not work in an ATM but try the next one. I carry three debit cards tied to different accounts. Always try to use them the first day or so just to make sure everything is working. In Amsterdam on the first day and all three cards failed to work at the first ATM machine. Now, a little panic did set in. Thirty minutes later found another ATM and all three cards worked.

The only credit card I have is a Discover Card which I believe is not used in Europe

Get another credit card. You have much less ability to dispute charges with a card that pulls money right out of your checking account than you do with a credit card. A few examples: you cancel a hotel reservation but they charge you a no-show fee. Restaurant runs your card twice (which actually happened to us last summer).

I carry three credit cards, two of which are from my bank and one from my brokerage account. This year I only carried one debit card from my “trip” cash brokerage account which has limited money in it for security. I left the other debit cards home because I have not needed them in the past.

Last year in France I used almost no cash. Everything was tap to pay, even the 69cent bottle of water. This year in Germany, Czech Republic and Austria I used a lot more cash, especially in Munich. Cash was preferred for transactions less than €10 and sometimes less than €20. A few restaurants were cash only.