Court documents show 31-year-old Wardell Hall and 23-year-old Rico Jerome Miller entered pleas Thursday in West Palm Beach.
They face a minimum of three years prison and a maximum of 10 years at sentencing in October.
Authorities say Miller brokered the trip with Hall for $2,400.
The passengers attempting illegal U.S. entry were from Jamaica, Trinidad and Ecuador.
Passengers told investigators they boarded a boat in the Bahamas in April and were to be dropped off near Miami.
Instead the boat became disabled east of the St. Lucie Inlet and was intercepted by a Coast Guard cutter.
The boat eventually sank.
No one was injured.