This was decided by the state government today in view of the Supreme Court direction to it to take a stand on the plea of the Italian authorities to move the marines away from the Central Prison.
Borstal school, where the two marines will be kept in Kochi, is normally used to lodge delinquent offenders.
State Home Minister Thiruvanchur Radhakrishnan said the government would inform Kerala High Court of its decision when the bail plea of the naval guards come up.
The marines, Latore Massimilliano and Salvatore Girone, have been in judicial remand for the last three months and lodged in the Poojappura Central Prison here.
They have moved the High Court for bail after the district court in Kollam rejected their plea.
The naval guards onboard Italian oil tanker 'Enrica Lexie' were arrested on February 19 and charged with murder of fishermen Valentine Jalastine and Ajesh Binki, who took to sea from Neendakara in Kollam, after they fired at them apparently mistaking them for pirates.