The man, who a friend identified as Taylor Watts, did not resurface after landing in the water, witnesses told SDFRD officials.
Officials said a lifeguard immediately jumped into the water from the pier to search, and a lifeguard boat also joined the effort. A lifeguard on a personal water craft and Copter 2 also assisted in the search.
According to SDFRD officials, at one point, there were about 16 lifeguards in the water searching for Watts. Crews also searched under the pier near the pilings.
The search was called off at 7 p.m. -- around the same time a U.S. Coast Guard helicopter and boat joined the search effort.
San Diego Lifeguard Lt. Andy Lerum says according to reports Watts climbed over the railing and was holding onto a rope when he fell backward and into the water.
San Diego Lifeguards resumed their search for Watts Monday morning with about 30 people. They told 10News his family in Houston had been notified and arrived in San Diego Monday.
Despite calmer conditions Monday afternoon, divers were unable to locate Watts. In addition to divers, the department utilized helicopters and boats with sonar equipment to widen the search.
"It's an unfortunate situation, the area is so vast. What we're trying to do, what makes the most sense with our available resources and that's focusing on the most likely area we think the person is," said Lerum.
Lifeguards will resume their search Tuesday morning, at last check they had not decided which assets they would be utilizing.