(CNN)Tourists currently on holiday in Greece have one piece of advice: bring extra euros.
Jeff and Jennifer Buxton of Texas learned that after they got off a ferry boat from Corfu Island on Sunday and began a three hour drive to Athens.
They started to run out of cash.
"We joined the locals as we hopped from ATM to ATM in search of one willing to give us euros, but found none," says Jeff, who is also traveling with his eight-year-old son Judah and 10-year-old daughter Jadyn.
"Thankfully, it turns out we had just enough cash on hand for the remaining tolls from Patras to Athens after all."
The family arrived in Athens with € .90 left in their pockets -- a dollar.
The ATM machine in their hotel still had cash to dispense. Later, the hotel staff asked to settle their credit card bill early just in case bank machines would stop working.
"We were only slightly inconvenienced. It's a sobering time to be in Greece right now. I pray for the Greek people that they will find the courage and strength to weather this storm," says Jeff, a technical director who runs the Meanderbug travel website with his wife.
"If you're coming to Greece, tourist planning at this point means bringing enough cash and using your credit card as often as possible."
That's the same advice from leaders in the Greek tourism industry after talks crumbled between the Greek government and its creditors over the weekend. In response, Greeks lined up at ATMs and ran them dry.
No guarantees of ATM cash
The country's financial situation grew even more perilous after it officially missed a $1.7 billion International Monetary Fund repayment deadline.
Uncertainty was heightened late last week when the Greek government scheduled a July 5 referendum vote on terms for a bailout offer.
Banks have been ordered to stay closed until the vote and capital controls have been enforced on Greek bank account holders, limiting withdrawals to €60 ($66) per person.
"Restrictions on withdrawals do not apply to our foreign tourists. Credit cards and debit cards issued from abroad can be used at cash machines freely," says Andreas Andreadis, president of the Greek Tourism Confederation known as SETE.
Although ATMs are working, it isn't guaranteed cash will be in them.
Andreadis says another option is to ask hotels for cash in exchange for credit, in an emergency.
With an expected 25 million visitors this year. set to contribute up to a quarter of Greece's income in 2015, SETE is advising Greek tourism professionals to accept all credit cards so their holidays are as smooth as possible.
"We understand that some businesses have obligations in cash, but we only hear of a few incidents, out of the hundreds of thousands of tourist transactions, that someone will not accept a credit card."
Fall in bookings
Since the weekend's turn of events, Andreadis says new vacation bookings have dropped, and there are some cancellations for vacations scheduled within the next few weeks.
He says bookings for later in the season remain steady.
Hotel supplies may not be as steady, as imports to Greece have frozen due to capital controls.
"Imported food and beverages can last up to 10 more days. At the moment, it is business as usual and there are no problems with supplies of food. We do hope that from next week the political situation will improve and that means a normal flow of imported goods.
"We are concerned with the situation and we in the tourism industry do hope there will be a deal with our EU partners."
So does Alkis Panagopoulos, the CEO and owner of the four-star Eden Beach Hotel Resort in Athens.
"We made our supply purchases for two weeks but after that it is hard to plan."
He says Sunday's referendum vote will be telling.
Panagopoulos says only one tourism segment is being affected by the recent turn of events.
"We've only seen cancellations from the Greek tourists. We haven't seen concerns from our international guests. The only action a few of our international tourists have chosen is to raise their credit card limit."
According to Mina Agnos, president of Travelive, a tour company that specializes in customizable luxury vacations in Greece and the Mediterranean; it's always smarter to travel with more forms of payment.
She says her travel advice to her foreign clientele hasn't changed much since last week.
"We just advise that tourists carry more cash. While there aren't any restrictions on the tourists here, you may run into an ATM machine that doesn't have cash."
Agnos also advises clients to inform their card companies where they will be traveling to avoid any problems with large payments and to look into fraud protections.
'A world away from Athens'
"What is happening is concerning for the Greek population and it's playing out in the news, so we're following it," says Agnos. "The fact is that Greece has seen a lot of issues over the years.
"From our standpoint, the situation doesn't seem to be as difficult in previous years. When it comes to tourists, it's hard to say they've really seen the effects of the crisis, especially in the islands where we know our guests are having an amazing stay right now."
On the island of Santorini Manthos Sotiriou, owner of the Volcano Dive Center says the realities of the country's crisis hit unexpectedly when ATMs ran out of cash over the weekend.
"I was a bit nervous when we ran out of money. Now, everything works perfectly and there is no problem at all. Tourists here are using their credit cards and ATM machines with no issues at all, thank goodness."
Sotiriou is also grateful hasn't seen any cancellations so far for his diving services.
"Santorini is a beautiful island and hugely popular among tourists. We're a world away from Athens. Despite what is going on, I still think this season is still going to be the best."
As for the Buxton family, they're enjoying every minute of their Greek vacation and plan to explore the island of Evia next.
"So far, we've loved seeing the historic sites and truly enjoyed the great Greek food that we ate with local people," says Jennifer Buxton, who hasn't had any problems with cash or credit since Sunday.
"Bring enough euros for your travel; don't just rely on your credit card. Come and see this beautiful country."