Before the finale, any locker key a character finds is solely the possession of that character. If you pick up, say, E-2 as Akiyama, the key is essentially gone until the finale, when the four characters pool their resources and inventories. After the finale, and during Premium Adventure mode, locker keys go into the shared inventory and can be used by anyone.
A locker key is often visible as a gleaming point of light within the game world, which makes them considerably easier to spot at night. They're often concealed by weird camera angles or hidden just above your usual field of vision, and many locker keys can only be picked up if you zoom in on them with the R3 button.
As early as chapter 1-2, you can get a Locker Key Radar from the Man Who Wants To Use Lockers on Taihei Boulevard, right outside the Kamuro Theater tunnel. Another one is available for sale at Ebisu Pawn for a frankly exorbitant price, and you'll receive a third as a reward for defeating the leader of the Kanto Gangsters as Kiryu (see the Emblem Collector trophy, below). With a Locker Key Radar equipped, you'll hear a loud pinging sound whenever you're within a few feet of a locker key, which speeds up as you get closer to the key itself. This is the only realistic way to find a couple of the better-hidden locker keys, but it's not an absolute necessity.
Locker keys do not appear in an area if that area is currently hosting an action sequence. For example, there are several keys hidden in the Theater Underground, but Akiyama cannot pick them up during 1-4 because he's too busy brutalizing yakuza.
If you open all one hundred lockers in Kamurocho, your currently active character receives an email from Bob, one of the clowns in Naomi's Palace. Stop by to receive the Beads of Good Fortune, an accessory that, when equipped, prevents you from getting into random encounters with yakuza on the street. You'll still get police scanner reports as Tanimura and run into the cops as Saejima, but at least you won't get mugged every block and a half.
Taihei Boulevard
These fifty keys can be found on the streets of Kamurocho, or inside various businesses. They unlock the lockers in the Kamuro Theater tunnel on Taihei Boulevard.
| A-1 | Tattered Scarf | At the southern intersection between Nakamichi St. and Nakamichi Alley, kind of across the street from the Café Alps. |
| A-2 | Steel Mail | During the day, there's a guy on Pink Street who offers you a chance to "see the babes" for 3,000 yen. Take him up on it and he'll let you into Asia, where this key is lying on the floor of the lobby. |
| A-3 | Spicy Knife | On top of a small file cabinet near the lockers themselves in the Kamuro Theater. |
| A-4 | Demon Stone | In a potted plant in the corner of Beam. |
| A-5 | Eye of the Dragon | On the floor in the second aisle of the Poppa convenience store on Showa Street. |
| B-1 | Hyper Stun Gun | Zoom in on the left side of the sign over the tunnel containing the locker bank on Taihei Blvd. |
| B-2 | Shape Memory Spring | Outside Marimba in the Champion District, in the corner of the alley. You'll probably find this in 1-4 when Akiyama has to go to the bar. |
| B-3 | Pearl | On the floor of the Ebisu Pawn shop, on the left as you enter, behind the central display case. |
| B-4 | Mystery Stone | On a ventilation duct outside the Kamiyama Weapon Shop. |
| B-5 | Mystery Stone | In the alleyway behind Kotobuki Drugs, on a pipe above a couple of blue trash cans. |
| C-1 | Ancient Steel | Right outside Kanrai on Shichifuku St. East. |
| C-2 | Broken Radio | In the M Store, against the back wall by the cold case. |
| C-3 | Blackjack Amulet | On a table against Bantam's back wall. |
| C-4 | Tauriner Maximum | On Park Blvd, a little ways west from the taxi stop on the north side of the street. |
| C-5 | Zero Jewel | On the floor in front of the counter inside Kotobuki Drugs. |
| D-1 | 1-1-1 Card | On top of a blue vending machine against the Shichifuku Street side of the Club SEGA in Theater Square. |
| D-2 | Toughness Emperor | Inside an open bathroom right across the alleyway from Homeland's front door. |
| D-3 | Silver Plate | If you're facing Homeland's door in Little Asia, turn left, then take the first left and go up the stairs. The key is on a catwalk up here, which puts it in a perfect position to set off the Locker Key Radar from inside half the important rooms in the neighborhood. |
| D-4 | Physimagic Jersey | There's a row of parked bikes outside Don Quixote on Showa Street. This key's in the basket of the bike on the west end. |
| D-5 | Charisma Ring | In an empty parking space on the east end of Taihei Blvd. East, on the south side of the street. |
| E-1 | Piss Mountain Stone | In a tree outside Millennium Tower's left entrance. |
| E-2 | Goddess of Children Amulet | In the middle of Tenkaichi Street, right outside New Serena. If you don't find this during Akiyama's part of the game, you may actually be blind. |
| E-3 | Small Motor | On top of a light fixture in the corner of New Serena. In Premium Adventure mode, the fixture in question is directly behind Haruka. |
| E-4 | Gravity Converter | Examine the pile of collapsed cardboard boxes behind the western entrance to the Underground Mall on Showa Street. The only way to know this key is here is to wander by with the Locker Key Radar equipped, as it does not appear to show up under any other circumstances. |
| E-5 | Antique Chain Mail | In the dead tree in Children's Park. |
| F-1 | Staminan Spark | From Chapter 1-4 onward, in the New Serena Backlot outside Sky Finance, on top of a building to the left of the vending machines. You need to zoom in on it in first-person view to see it; it's actually well overhead. |
| F-2: | In the small playground in Tenkaichi Alley, underneath a park bench. | In the small playground in Tenkaichi Alley, underneath a park bench. |
| -3 | Pearl | In the aisle between the tables in the Orchid Palace. |
| F-4 | Comfy Soles | Go into Kyosho No. 1 Star and head towards the back wall, past the clerk at the counter. The key's on the floor in front of the back door. |
| F-5 | Mystery Liquid | In a tree on Millennium Tower North. |
| G-1 | Royal Joker Card | Inside the Nakamichi Street Club SEGA. |
| G-2 | Even Goro's Beads | On southern Senryo Avenue, inside a lamp on the second floor of one of the nearby buildings. This is the same side street where you go to rescue Zhao during Tanimura's substory "Another Case." |
| G-3 | Lopsider Cigarette | Among the parked bikes behind the Club Sega on Nakamichi Street. |
| G-4 | Red Jewel | Right inside the Café Alps, near the front door. |
| G-5 | High-Grade Platinum | On an awning in the northeastern corner of the Champion District. |
| H-1 | Chunk of Wood (Maple) | On the north side of Shichifuku Street, inside MEB. You may not actually recognize this is a storefront at all at first, but there's a very common random encounter in this area that involves somebody, either you or a random gang member, getting thrown through its window. |
| H-2 | Staminan Spark | On Suppon St. at the dead end to the west, south from Sky Finance. |
| H-3 | Shoulder Pads | Right outside the Taihei Blvd. Matsuya store. If you're facing the door, it's to the left, on top of the posts above the parking lot's entrance. |
| H-4 | Silver Plate | Underneath the giant billboard in Theater Square. |
| H-5 | Lotus Clan Broadsword | In the alley directly behind Homeland in Little Asia, which means only Tanimura can get it. It's on a pipe well above street level. |
| I-1 | Chunk of Wood (Ash) | Outside Kanrai, on top of the sign across the street that reads CENTURY. Warning: Don't pick this up as Akiyama, leave this key for Saejima |
| I-2 | Super Resin | Outside the Volcanic Volcano underneath a vending machine, on Theater Ave. |
| I-3 | Modified Lighter | In the Kamuro Theater tunnel, on the ceiling above the vending machines over by the escalators. It's most readily visible if you descend the stairs from Theater Boulevard. This is the area where the sketch artist is hiding during Tanimura's substory "The Witness." |
| I-4 | Charismatic Photo | On Shichifuku Street, on the south side of the block that contains the Yunosono Hot Springs and Kanrai. It's on top of a sign that reads COFFEE BARRON [sic]. |
| I-5 | Seal of the Dragon | Right outside the stairs down to the Kamuro Theater tunnel, north of Theater Square, at the top of a column. During the day, there's a guy in sunglasses standing directly underneath it. |
| J-1 | 1-2-3 Gum | In the middle of Pink Alley. Saejima practically trips over it during 2-4. |
| J-2 | Large Blow-Up Doll | Next to the koi-koi dealer in the gambling hall in Ryugujo. |
| J-3 | Broken Radio | In the Yoshida Batting Center's lobby, inside an air vent above the arcade machines. |
| J-4 | Ruby | Inside Mach Bowl, just outside the women's restroom. |
| J-5 | Trips Yokan | In the Hotel District, halfway up a telephone pole in front of the Hotel Volescia. It's south of the taxi stop. |
