Take the 2 tracking devices from the Town Center of Al Sharim Pass dead drops.
Be careful, there are a lot of armored bots nearby, and there may be a Juggernaut.
Plant a tracker on top of the submarine in Hafid Port.
The submarine is inside the building, climb on top of the boat to install the tracker.
Plant a tracker on top of the submarine in the Ashika Island Waterways.
The submarine is in the underground tunnels. Be careful, there are many bots and there may be two Juggernauts. Jump on top of the boat to install the tracker.