123Travel recommends Multi-Currency Cash Passports. Use your Cash Passport In-store, online or at ATMs just like you would a credit or debit card, except with your own prepaid funds. Load up to 10 different currencies on the one card. USD, EUR, GBP, NZD, THB, CAD, HKD, SGD, JPY and AUD.
Locked in exchange rates means you know exactly how much money you have to spend.