The search was called off around 8 p.m., nearly 24 hours after the teenager was first reported missing.
"The decision to suspend an active search is never easy and is only made after exhaustive efforts to find the missing person," said Capt. Stacey Crecy, commanding officer of Coast Guard Sector Los Angeles-Long Beach. "Our hearts ache for his family and friends."
The teen, described as a 15-year-old boy, went missing after going in the water Sunday night. Authorities said he went swimming with a friend near tower 11 but never made it back to shore.
"We've been actively searching since 9 p.m. last night. We're currently searching from the Huntington Beach Pier to the Santa Ana River," Frank Lower with the U.S. Coast Guard said earlier on Monday.
Witnesses say the tide came up fast and the waves got bigger while the teens were swimming, and the boy was swept away.
Some of his friends, like Love Che-Howell, heard about what happened and rushed to the beach to help.
"It's pretty heartbreaking because he was one of my really good friends," she said. "We just came out here and started looking for him on the beach, and we just saw there were cars everywhere. There were helicopters. The whole ocean was lit up. There were lights shining everywhere."
Another friend, Brooke Gramata, said the 15-year-old is set to start his sophomore year at Huntington Beach High School in the fall.
"I was in a swim PE class with him for a little bit. He's a pretty good swimmer, but I heard the tides were really, really strong," Gramata said.
For privacy reason, Eyewitness News will not release his name at this time but his classmates are holding out hope he will be found safe.
"I'm kind of still shocked," Gramata said. "It's hard to process because just the other day we were texting and just joking around sending each other funny videos."
Prior to calling off the search, the Coast Guard was working with local authorities, like the Orange County Fire Authority and Huntington Beach police.