Vladyslav Cherniavskyi, 37, and Oleksandr Yavtushenko, 43, appeared in Portsmouth Crown Court where they pleaded guilty to three charges of assisting unlawful immigration, the National Crime Agency has confirmed.
The pair are due to be sentenced at the same court on December 12.
The charges follow an NCA-led interception of a yacht near the Isle of Wight on July 20.
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The vessel, escorted into Gosport Marina, carried four migrants: three Albanian males and a Vietnamese female, according to the NCA.
NCA senior investigating officer, Julian Harriman, said before the case was brought to court: “This operation was part of an ongoing NCA investigation led jointly with French judicial authorities and Gendarmerie Nationale, which has been supported by Border Force.
“Tackling people smuggling gangs remains a priority for both France and the United Kingdom and we are determined to do all we can to target, disrupt and dismantle the criminal networks involved.”