San Juan, like any other big city, has its share of petty crime, so guard your wallet or purse on the city streets. Although you certainly can—and should—explore the city and its beaches, use common sense. Don't leave anything unattended on the beach. Leave your valuables in the hotel safe, and stick to the fenced-in beach areas of your hotel. Always lock your car and stash valuables and luggage out of sight. Avoid deserted beaches at night.