The navy rescued 63 migrants in distress after their dinghy started to take in water overnight, a statement said, and 99 in a similar incident on Wednesday.
A patrol boat rescued another 61 migrants after they made a distress call, and then 147 more in a third rescue, the navy said.
The rescued migrants, including many women and children, were taken to Malta for health checks.
Malta has appealed to the EU for help in dealing with the flow of migrants, which its much larger neighbour Italy has begun to turn away.
Italy's hardline stance has increased pressure on the island nation of 450,000 people, which was already a common destination for migrants trying to cross the Mediterranean from North Africa.