Money - Currency and Usage
Puerto Rico is part of the United States. The currency is the U.S. Dollar. No other currency is accepted as an alternative, you should convert your currencies upon arrival.
As with any large city, do not flash your cash around. That is an open invitation for scammers and n'ar do wells.
Though rare in the tourist zone, thievery does occur. Don't take valuable watches or large sums of cash to the beach. You will be constantly watching your belongings instead of enjoying the sunshine.
Traveller's checks will be welcome in larger venues such as your hotel. However, Puerto Rico has many vendors that have never heard of traveller's checks. Don't arrive thinking you can rely solely on traveller's checks and cash them quickly. Not only do you need to find someone to cash them, but you need to be sure that they're open. Puerto Rican's have lot of holidays. You might not find a bank that is open for another three days upon arrival. Refer to the map below for Western Union locations that might be able to assist.