Locking mechanisms are obstacles found in Metroid Prime 2: Echoes and Metroid Prime 3: Corruption used for security purposes. They appear as a series of inter-connected node targets that cannot be removed one by one. A weapon capable of firing five or four projectiles at once is required to disable the nodes and unlock what they were guarding. The nodes can appear either by themselves or attached to a Multi-Lock Blast Shield. Samus uses the Seeker Missiles once she has acquired them to disable locking nodes. Sometimes the locking "mechanism" is naturally formed, such as supports for the Chykka Larva cocoon in the Dark Torvus Temple and the boney structure that Missile Blockers in the Elysia Seed are able to grow.
Most locking mechanisms in Echoes appear on Multi-Lock Blast Shields, but there are a few instances where they are not attached to one. Certain gates in the rooms Sacred Bridge and Temple Access, and a Portal barrier shield in the Hive Dynamo Works, are attached to locking mechanisms. However, these mechanisms are invisible in the Combat Visor, requiring the Dark Visor for Samus to see and disengage the locks. The System Control Rings in the Ing Windchamber need Seeker Missiles to raise Grapple Points in the Grand Windchamber. Samus must then fire at the Rings again to dislodge them and provide access to the Sunburst back on light Aether.
There is only one Multi-Lock Blast Shield in Corruption. Locking mechanisms are found in the Concourse and Transit Hub keeping the Second and Third Bomb Components locked in, and must be disengaged so that Samus's Gunship can collect them and assemble the Theronian Bomb. The Concourse also features another locking mechanism attached to a retractable wall that provides another access point for the main walkway. In Zipline Station Bravo, the large cannon that can fire Samus back to the Transit Hub requires locks to be disengaged. A type of door similar to the Multi-Lock Blast Shield is present in the Xenoresearch Labs and allow Samus to move throughout the area once she acquires the Seeker Missiles within the Labs. Locking mechanisms also appear in the Command Vault where they release the X-Ray Visor, in the Airshaft where they release Wall Jump Surfaces, and at the entrance to the Powerworks to enter the room.
- Chykka supports
- "Object scan complete.
Organic structure designed to support cocoon. Destruction of supports will release cocoon."
- Control system (Echoes)
- "Indestructible barrier shield.* Scans indicate presence of a control system.
Interface method unknown. Control units not present in the visible spectrum or current timespace."
- General (Corruption)
- "Locking mechanisms activated. A simultaneous blast to all targets is required to disengage locks."
- Safety cap (Zipline Station Bravo)
- "Safety cap is blocking access. All connected targets must be shot simultaneously to destroy cap."
- Elevator lock (Concourse)
- "Elevator lock is controlled by connected targets. Hit all targets at once to restore elevator power."
- Missile Blocker (Elysia Seed)
- "Boney structure appears to have multiple weak points. If they were hit simultaneously, it could be destroyed."
- Power nodes (Powerworks)
- "Power nodes offline. Hit all targets simultaneously to restore power to them."
* This sentence only present in the scan for a barrier shield in the Hive Dynamo Works.