The convoy began its journey on Sunday but was forced to turn back less than a day later after the Spanish weather agency AEMET warned of a storm in the region.
The smaller boats in the convoy may not have withstood such harsh weather, announced the so-called Global Sumud Flotilla.
By 8 pm on Monday, the boats were able to set sail again, reports AFP.
On board are, among others, environmental activist Greta Thunberg and the newly minted political wild card Lorena Delgado Varas. The intention of the Global Sumud Flotilla is to "break the illegal siege" of the Gaza Strip by opening a humanitarian corridor by sea.
It should not be up to us, said the world-renowned activist Thunberg to the media before departure.
It is the responsibility of countries, our governments and elected officials, to act to uphold international law, prevent war crimes and genocide. It is their legal duty, and they are failing.
