This article contains possible spoilers. Read at your own risk!
Collectible Dog Tags are featured throughout the singleplayer campaign of Battlefield 4, functioning similarly to Collectible Weapons. When near a dog tag, a noticeable chime will trigger. Once found, Dog Tags can be utilized in multiplayer. There are a total of twenty-two collectible dog tags throughout the campaign.
Located in the very first room on the right side of the hallway at start of level. When entering the room, a knife can be seen holding the tags to a bulletin board on the left wall.
Reference to Shakespeare
One Way Trip
Near the courtyard. Before dropping down into the room where the first gadget weapon cache is located, jump over the hole in the floor to obtain the tags that are stuck to the shutters of the middle window.
Found after the building collapses on and Recker is forced to amputate Dunn's leg. Before getting in the car to leave the area, move to the front of the crashed helicopter to retrieve the tags in the seat of the copilot.
Found by making a right down the alley way where the mission starts, head left at the end and listen for the chime. The tag will be stuck to the door in the middle with a glowing red light.
Going Up?
After reaching the hotel, enter the lobby and take the elevator. Once exiting the elevator look up and the tag is located above the elevator door.
One-Man Riot
Obtainable after finishing up in the hotel and making way back to the alley ways in which the level started. A tank will chase the squad down these until coming across an area it can't reach. The chime will occur. Head to the right past a tree and see the tags on the gate just behind this tree. Be aware there is a tag that is uncollectable located in the dead end alley before the broken gate that needs to be dropped down to reach the other side in order to get to the tree.
Reference to popular artwork by graffiti artist Banksy
Found by heading down the first hallway when the level begins. Look for the two men near the glowing red light at the end. Just before reaching them, the chime occurs and there is a barracks room on the right. Head in and the tags will be at the head of the top bunk.
Carcharodon
The tags are found underwater after reaching hatch G-46. Follow the squad to the room in which they surface. In this room, the green glowing door adjacent to the entrance has a brown pillar to its left. The tags will be there.
Carcharodon is a genus of shark that includes the Megalodon.
After Hannah is rescued from the infirmary, go outside. The squad will go left. Instead, go right and look for the crashed helicopter of the deck. In the copilot seat is the dog tag.
On the beach where the level begins, there is a while boat along the beach to the left. Circle around to the side facing the water and grab the dog tags.
Armored Column
Inside the club (the same club Hannah and Irish get into a verbal scuffle), go behind the bar with the red stools and look near the floor to the middle. The dog tags are there.
The image is a reference to tactics the Ancient Roman Army and many others used in battle
Grounded
After reaching the hangar with the large white and blue passenger plane, the thirds and final tags on this level will be on the plane's left wing. Reach it by using the ramp next to it in order to hop on. Scale the wing to the body of the plane and the tags will be on the door.
After meeting back up with Irish after rescuing him, look for the dark holding cells in the next room to the right. Go to the furthest cell and see the glowing dog tags on the left wall of this cell.
Located near an easter egg of the Workbench from Dead Space 3
Freedom At Any Cost
In the room where Recker must protect Dima while he hacks the control room, climb up to the catwalk and scale the left wall. There is an electrical box with a knife stuck in it. This knife holds the dog tags.
The Shaw Shanked Redemption
Before heading up the large ramp to take the tram down the mountain, go under this platform and walk to the ledge. Look down over the middle and see the dog tags sticking out.
After reaching the building in the park with the blue blankets hanging above the staircase, there is a blue truck in front of this building. In order to obtain these tags, the truck will need to be destroyed. After, enter the truck through the rear and grab the tags near the cab
Destruction Enthusiast
After moving downhill and onto the compound, a helicopter will attack. Once this has been dealt with, climb the yellow ladder on the left to reach the top of the office building. Look out to the black scaffolding. Hop over to it and snag the tags on it.
The image is a reference to grenade from Battlefield: Bad Company
On the left side of the deck, there is a white plane. Clear out the enemies and scale the plane using its right wing. Get on top and head to the back of it. The knife holding the tags jutting out from the side.
Reference to the television show, Battlestar Galactica. Admiral Adama (Edward James Olmos) is a fictional Fleet Admiral who protects and guards a surviving fleet from a nuclear apocalypse.
Rebel
After Reaching the infirmary inside the Valkyrie, the dog tags can be found behind the second set of curtains on the right side of the room on the gurney.