With the 380 men and 63 women were 49 children, who are not detained but whom government officials said are either in jails with their mothers, or under social services care if they were unaccompanied.
Under Canadian law, refugee claimants held in custody are entitled to periodic detention hearings by an adjudicator with the authority to release them.
The Sun Sea reportedly spent 90 days traveling from Thailand before police boarded it in Canadian waters and piloted it ashore in western Canada.
It was the second boat carrying Tamil migrants to arrive in Canada in less than a year, and other Tamil ships have been reported in other countries following last year’s bloody end to the 37-year war between Sri Lanka and Tamil separatists. The United Nations has said at least 7,000 civilians were killed in the finale of the war, and thousands of Tamils remain in camps in the country.