When in need for cash in a foreign country, one is presented with several options. They are, in order from best to worst:
Withdrawing with a credit card at a local ATM. This is a good option because the home bank will use the inter-bank rate for converting from foreign into home currency. Banks might charge an “overseas ATM use fee”, but those are getting rarer and have never been an issue with online banks like TransferWise or n26.
One thing crucial to keep in mind though is to never let the ATM do any conversions. Especially ATMs at airports or stations will commonly offer a “fixed rate conversion” and tout it as a sure way to avoid conversion rate insecurity. However the only thing one can be sure about is to get ripped off by an extortionate exchange rate.
So when I’m in Croatia, I tell the ATM to charge my credit card in Croatian Kuna and not in Euro. One has to stay strong here. The ATMs will at times ask several times “are you sure you do not want us to convert for you?”.
Option number two for getting ones hands on foreign cash is to exchange in the destination country. Banks in the city often offer better rates than those at stations or airports, but still, one can expect to loose 3-5% here.
By far the worst (i.e. most expensive) option to aquire the exotic bills is by exchanging with a bank in a western home country. They will not only give a horrible exchange rate but on top of that often charge a conversion fee. The bottom line here can easily be a 12% loss.
To summarize: Get a credit card from any online bank (n26, TransferWise, Revolut), preload it with a couple hundred bucks and then get cash on arrival. Without taking any offers of “fixed conversion rates”. More details on the latter here: https://medium.com/@ChrisLettner/with-or-without-conversion-how-atms-get-foreigners-to-take-out-too-much-then-charge-extortionate-61737cdc4448