Travelers from or transitting through seven coronavirus hotspots, including Australia and the US, have to spend 14-days in self-quarantine outside those countries before entering Tonga.
Tongan nationals are exempt.
The chief executive of Health, Siale 'Akau'ola, said provisions had been made to quarantine them in-country.
Dr 'Akau'ola said some people could be isolated at home.
"But those who do not have that environment at home, then we have another place for them here prepared for those who can't be isolated at home."
He said the Taliai Army Camp near Fua'amotu airport had been readied as an isolation centre.