Of course, the group quickly went viral.
"We started serenading from February 1st to the 14th ... and we've been pretty busy," said the group's president Brendaitzel Torres. "The busiest days are the 13th and the 14th, which we started serenading from 7 in the morning all the way to 10 in the night."
Mariachi Orgullo de UCI became an on-campus organization two years ago, becoming the first mariachi band at UCI.
Torres was looking for a way to connect to her culture, and it didn't take long to find out that other students were looking to do the same.
"I'm very grateful for them because they're very dedicated," Torres said. "We love expressing our culture to campus, especially in such a diverse community like UCI."
The 15-person band typically performs at campus events, but nothing has been as popular as their serenades. They're saving the money they earn from the performances to purchase their own mariachi suits.
Emmanuel Patterson booked a serenade for his girlfriend, Alexandra Trejo - the two are currently in a long-distance relationship.
Patterson drove 500 miles Friday morning to surprise Trejo at UC Irvine and showed up at her front door holding flowers - and the mariachi band by his side.
"Her roommate told me about the mariachi, and she told me what her favorite song from them was, and so I booked it and I made the plan to drive down to her," Patterson said.
"It was really surprising because I wasn't expecting it," Trejo said. "I'm just seeing his face and I'm like, 'What are you doing here? Then seeing the mariachi band."
Student Evelyn Vaca was surprised at 7 a.m. by the band.
Her mom surprised her to make the holiday on campus feel a little bit more like home.
"It was really so nice, and I did not expect that at all for my mom to do that for me. It was so sweet," Vaca said.
Whether it's a gift from family far away or a grand romantic gesture, the magic of Mariachi Orgullo de UCI surely made this Valentine's Day one to remember.
"It's honestly probably going to be like my favorite one," Trejo said.