The local currency of the Maldives is the Maldivian Rufiyaa, which is a non-convertible currency and cannot be purchased beforehand. However, the US Dollar is widely accepted throughout the Maldives, especially at island resorts and hotels. If you arrive in Maldives with neither of these currencies, you can head to the Bank Of Maldivian Foreign Exchange, where your international currency can be converted to the currency you prefer with no hassles. The banks of Maldives are quite particular about the condition of USD they receive and any notes that are old, damaged or defaced will be rejected.
Big transactions can also be initiated by credit cards. Keep in mind that Maldivian ATMs charge 100 MVR (6.50 USD) per withdrawal. In such cases, keeping cash by making one large withdrawal reduces the surcharge.