The Spanish aid ship Open Arms arrived on Friday off the coast of Gaza.
The ship is carrying 200 tons of desperately needed food for tens of thousands of Palestinians displaced by more than five months of war between Hamas and Israel, according to France 24.
The aid comes after the United Nations warned again of the threat of famine in Gaza.
If the new sea route is successful, it may help to ease the hunger crisis affecting Gaza, where much of the population faces malnourishment and hospitals in the worst-stricken northern areas have reported children dying of starvation.
However, bringing in aid by sea and through air drops will not be enough to make up for difficulties getting in supplies by land, aid agencies have repeatedly said.
The ship left Cyprus on Tuesday.