The Israeli navy began unloading the 150 containers from the Klos C Sunday, the day after it docked, the Jerusalem Post reported. When the ship was captured last week, Israeli officials said they had "conclusive evidence" Iran was behind the shipment.
"Just walked through a hangar with rows of these rockets from the Iranian weapons shipment. All I can say is I'm happy they're in our hands," military spokesman Peter Lerner posted on his Twitter account.
The weapons experts were going to try to determine whether the missiles were ones with a 90-kilometer (about 55 miles) range or ones with a range of 150 (about 93 miles) kilometers to 200 kilometers (about 124 miles), the Post said.
Officials are expected to complete the unpacking and classification Sunday and present their findings Monday.
Israeli Prime Minister Binyamin Netanyahu and Defense Minister Moshe Ya'alon were expected to be at Eilat Monday.