The answer is yes if you use your common sense. Stay vigilant as pickpocketing and robbery are not uncommon. However, stick to the main road that is lit up at night, stay where it is more populated, and don’t get drunk and act foolishly. That just makes you a target. Don’t let that put you off going, though. You can have a great time in Tulum (and anywhere in Mexico, really) if you pay attention to your surroundings and stay alert. As you should in any country.