The man was first reported missing around 10:30 p.m. Sunday night near the breakwater. According to the U.S. Coast Guard, two people were on separate jet skies but were unable to get back onto the watercraft.
A woman was rescued and brought back onto land near the Ballast Point Brewing. She had minor injuries.
Crews were unable to find the man riding the other jet ski and remained on scene searching for him overnight.
The Coast Guard and Long Beach Fire Department were helping in the search.
Additional details were not available.