Underneath the Founders’ Island is the Port Adams Subway station where you can find 8 Riddler trophies. You must access the subway from the south section of the Founders’ Island at a certain point in the main story before facing off with Arkham Knight. Like all the trophies, it is best to go after these after you have defeated the Arkham Knight or beaten the game.
Where to find all Riddler Trophies in Port Adams Subway?
Riddler Trophy #1
Map Coordinates: 3109, 1425
At the end of the subway section where 3 branching paths head inside different paths of caves, check the pipes above to find the collectible.
Riddler Trophy #2
Map Coordinates: 3109, 1425
This collectible is located near the end of the subway part of the tunnel, in the large open area with the ramp and moat. You need to head over to the opposite side of the moat and find the collectible on top of a small room.
Riddler Trophy #3
Map Coordinates: 3109, 1425
Take the elevator down using the Batmobile in the Subway Tunnels and look at the raised platform that contains the collectible.
Riddler Trophy #4
Map Coordinates: 3109, 1425
You need to reach the area with a bunch of drones that you need to sneak past and find a small alcove on the right side to find another collectible.
Riddler Trophy #5
Map Coordinates: 3109, 1425
From the 3 branching paths, head inside the tall cave with stairs leading upwards. You need to check the bottom of the stairs to find the collectible sitting on a small chair.
Riddler Trophy #6
Map Coordinates: 3109, 1425
Inside the Subway Tunnels, keep on driving through the caves until you come across a section full of pipes, sewage, and large grates. You need to grapple on top of the large grates to find the collectible.
Riddler Trophy #7
Map Coordinates: 3109, 1425
You need to head over to the north side of the caves in the Subway Tunnels and search the area on your left to find the collectible.
Riddler Trophy #8
Map Coordinates: 3109, 1425
From the 3 branching paths, head inside the tall cave with stairs leading upwards. Once you are in the area, grapple on top of some pipes with a walkway to find the collectible.
