- More than anything else, January on the island is known for Three Kings Day, which has its own traditions.
- The San Sebastián Patron Saint Festival brings tens of thousands of revelers to Old San Juan.
- January also kicks off whale-watching season in Rincón and the west coast of the island.
- January 4: The mayhem and mania of World Wrestling Entertainment (WWE) comes to Mayagüez.
- January 6: In Puerto Rico, the Three Kings rule the Christmas season. Puerto Ricans celebrate December 25, but don't forget about January 6, El Día de los Tres Reyes Magos, or Three Kings Day. An old-fashioned tradition calls for children to gather grass and place it in a box at the foot of their beds, so that the camels of the Three Kings will have something to eat when they come to visit. While it is a revered holiday throughout Puerto Rico, nobody does Three Kings Day quite like the small, southern town of Juana Diaz, whose Three Kings tour the island before making the voyage home. In Old San Juan, head to Luis Muñoz Marín Park for the live music, parades, food and drink, and plenty of revelry.
- January 17-20: The largest street fair in Old San Juan is the San Sebastián Patron Saint Festival, when thousands descend on San Sebastián Street to commemorate and celebrate. It's by far the biggest patron saint celebration on the island. Expect fairground rides, food stalls and live music, parades of traditional Puerto Rican masked figures called vejigantes, and plenty of dancing at night. A day earlier, the town of San Sebastián kicks off its own festival to honor its patron saint.
- January 25-26: Puerto Rico Jazz Jam brings two nights of smooth Jazz beats to the venerable Teatro Tapia in Old San Juan.
- January 25-27: Hard-core cyclists will want to register for La Vuelta Puerto Rico, a three-day, 375-mile spin around the island. Registration is open until January 15.
- January-February: It's whale-watching season in the west coast of Puerto Rico, when humpback whales can be spotted off the coast. An excellent spot to see them is the observation park at the Rincón lighthouse.