Rescue boat "Astral" helped over 100 migrants travelling from Tunisia to Italy's Lampedusa, the charity said.
One rescue mission saw the crew of the 30 metre-long boat rush into their speed boat to provide migrants, navigating in overpacked wooden boats, with water and life jackets.
Unlike its bigger brother, the famous "Open Arms" tug ship, the "Astral" is not big enough to take migrants on board, so it had to accompany the migrant boat until a ship from the Italian Guardia di Finanza arrived in the area to assist them.
The Guardia di Finanza also said it had rescued more than 100 migrants travelling in five boats and took them to the Italian island of Lampedusa. According to Italian interior ministry data, the number of migrants arriving in the country so far this year has more than doubled since last year.